buzzthefuzz

i recently took ownership of my parents 1986 trans am with the 305 tpi. besides the body rust issues i need to deal with, hopefully sooner than later, the car is in great shape. the motor runs exceptionally well, especially for having 222,000 miles on it. a new bushing kit should be all i need to get it handling how a car equipped with the ws6 option should handle. but i need to keep this thread on topic, so here we go...

basically i want a daily driver that can still toast most of the little ricers running around here in the seattle area, while keeping the car relaxed and not about to break at the twitch of the throttle. ive gathered from these forums that with a new cam, intake, and a boost in fuel pressure i can expect about 250hp. Im am NOT a car guy by any means, but i do have an affection for machines and i think form over function is a beautiful thing. i know some ppl here might cringe at the idea of a noob screwing around with a tpi setup, but im here to learn.

How can i get her over the 300whp mark and keep everything in line mechanically without breaking the bank? Id also like to try and keep my mpgs from plummeting, but i guess everything has its trade offs. it has the 4 speed automatic which is obviously going to need different gears over stock, would it be good to change the gear in the rear end too? i believe it has the 9 bolt limited slip from the factory. how much porting, if any, is necessary to produce hp in that range?...and, maybe most importantly, is trying to make power out of a motor with that many miles on it even a good idea?

answers to these questions or answers to questions i didnt ask but you feel need to be answered to keep another dumbass with a dream off the road are perfectly welcome. im broke at the moment but whenever i start making money again this thread will be host to many more questions im sure. if anybody wants a pic of something on the car just ask.

hondamaniac

iTrader: (2)

The very first response these guys will tell you is to drop in a 350. For some reason keeping a car with numbers matching has no meaning to most of those on here. It's all about doing as many modifications as possible.

I will be doing something similar to what you are trying to do. I want 300 rwhp out of mine also. The first thing I wold do is pull the motor and get it rebuilt. Talk to the guy who is going to do it for you and together you can come up with a good estimate of what you are looking for. Together you can take into account, finances and other restrictions you have. Since you don't have much experience that would be the best start to your project.

InfernalVortex

iTrader: (4)

Because it means absolutely nothing to have a "numbers matching" thirdgen. No one will care about 305 thirdgens in 10, 20, or 30 years. Having a numbers matching 305 is like having a numbers matching inline 6 in a first gen. Who cares?

There are good reasons to keep the factory setup (reliability, convenience, gas mileage, keeping the car generally stock, etc) but keeping the factory 305 because it's "numbers matching" is absurd. To make matters worse, the 86 305 TPI is probably the most awful of all of them.

There are certain cars I'd keep the stock 305's in them for value later on down the road, but the average mid 80s 305 Z28 or IROC isnt one of them. If it's got some nifty options or it's a rare package, keep it stock. Intact crossfire cars should be kept stock. Any pace car type car should be kept stock. TTA's, 1LE cars, LB9/T5/G92/1LE etc cars, even B4C cars are pretty neat, and worth keeping in tact if they're still in good shape and still mostly stock. I personally think with the low production numbers of them, the 91 and especially 1992 Z28's are good candidates for preservation in stock state. Medium/low mileage L69 with the good options (manual, 3.73 gears) are also good candidates to keep numbers matching. That means your car, if still mostly stock and in good condition, would be a good candidate. But understand if you start throwing performance parts on it to get to 300hp, then the "numbers matching" part of your car doesnt really mean much anymore, even if it's the same block.

A rusty 220k mile 86 305 is not a car that "numbers matching" will ever mean anything. Numbers matching doesnt really mean much for any cars beyond super highly optioned first gen muscle cars to begin with.

What does "numbers matching" really mean? Why is it important? Because if you're going to shell out big bucks for a rare, old, muscle car with a lot of rare options on it, you want a car that wasnt pieced together. You want a car that was ALWAYS a ZL-1 or an LT-1 or a Z/28 (applies to the rare 69 Z28s, not the later ubiquitous incarnations)and is ORIGINAL. It's like putting an L98 into a sport coupe, throwing ground fx on it, and claiming it's an aforementioned highly-optioned stock IROC and asking big money for it. You want numbers matching to make sure someone didn't take a vanilla car and put a bunch of fancy parts in it and mark it up. The sad truth is that 98 percent of all thirdgens are vanilla cars. Especially the 305's. This car could be interesting if its a manual and has a bunch of neat options, but 86 was a bad year for power, so an 86 305 TPI is probably the worst of all the LB9 cars. An 85 was the first year for the IROC so, IF it's a well optioned super nice LB9 car, it MIGHT be worth keeping it numbers matching, but if it's over 125k miles, it's already beyond the point where people shelling out big bucks for "numbers matching" cars are going to bother with it.

buzzthefuzz

i was expecting the 350 responses, but since im not trying to shave a second off my quarter mile or something, keeping the 305 till it cracks in half seems way cooler. you can drop a 350 in any old firebird, but mines a trans am... im the kind of guy who'd be fine following market trends with a big wad of cash so that i could make more cash, but when it comes to my hobbies, its my own reality dammit.

that does seem like a good plan, i was just hoping to one day soon get a place with a garage, then maybe one of my friends who are much more car savvy than i am could help with the motor rebuild. I am trying to learn as much as i can from this car and hope to be there for everything that happens to it.

the most fantastic plans i have for it is once the motors all souped up, i want to build a stealth twin turbo setup for it where the turbos are actually concealed at the bottom of the trunk compartment. obviously thered be a little custom fab involved, but damn, imagine looking under the hood and seeing a stock looking tpi motor, only to later see it stomping on some dudes ferrari... some stronger internals would probably be nice too i suppose.

regardless, i started this thread looking for help with making my 305 as strong as practicality allows. if not pushing my car immediately to my budgets power making limit sounds crazy to you, just pretend engine swaps are outlawed in my state or something and post accordingly.

InfernalVortex

iTrader: (4)

I dont understand... do you want to keep the car stock or not? If you're not, then wasting time with the 305 is just that... wasting time. Build a 383 or go for a Gen III/IV engine swap. Building a 350 is just too expensive for the amount of return you get when you compare it to teh cost of building a 383 or swapping a stock LS1 in. You end up with $3k+ invested and the car is going to be slower than a 2010 V6 mustang or Camaro. If you just want a cruiser, do a stock rebuild of the 305 and call it a day.

But since you say the car has rust issues, it's very likely cobbler fodder, meaning you should cobble together every sick twisted mod you can. Fix the rust (if it's even possible) and put a turbo gen III/IV 6.0 engine in it and go turn 9-10-11-12 second quarter miles. These types of damaged goods rusty high mileage cars are perfect for stuff like that. But just make sure the rust is fixable. If it's not it's destined for the scrap heap whether you like it or not.

The 305 isnt worth rebuilding, it costs at least as much as a 350 to rebuild, usually more, so just run it til it blows up. The other problem is you dont build a high power motor, and then later decide to turbo it. You build a motor from day 1 to handle forced induction. It requires a completely different build philosophy. For a naturally aspirated car you're going to want more displacement, more compression, more cam, and rely on free flowing intake and heads and exhaust to make power. For a turbo you need to spend a bunch of money on bottom end parts, keep the compression lower, and focus on a lot of serious fabrication to make it all work. There are a lot of parts in the build that require completely different considerations with a turbo car, and the engine needs to be built with a turbo in mind or built to be naturally aspirated.

You need to pick a route youre going to go and make that happen. Just understand that theres a WHOLE LOT MORE to turbos than just bolting them and some piping onto the car. There are multiple reasons the rear mount turbos aren't very common. Also realize that you can use one larger turbo instead of two turbos. There are good reasons for and against single and twin turbo systems.

buzzthefuzz

the turbo thing was more of just what i said it was, a fantasy... but lets say this is your car and you've already fixed the rust, and you had $1000 that for whatever reason you were only allowed to spend on the 305, what would you go with?

sorry, i keep making incomplete posts... my car does have rust issues but at least for now i think its to where i can save it. like i said before im really not interested in track times, im 21 and my only concerns at the moment are making girls take a second glance and making civics think twice. id just prefer to do it with the 305 until somebody drops that ls1 in my lap. (not literally)

InfernalVortex

iTrader: (4)

Any guy who is serious about his import is gonna be fast. They'll embarass you 9 times out of 10.

For $1000 the only thing you can raelly do is headers and exhaust. 3 inch mandrel bent cat back with Hooker 2055 headers.

85T/A350

A $1000 will get you no where near the 300whp in a 305. Like said above, that will pretty much only cover a good exhaust upgrade.

1983Chimaera

For $1000 I would source an LT1 cam and 4-pin coil-in-cap HEI from the junkyard (dirt cheap), get yourself a Megasquirt I or II ECM, build the adapter harness yourself (dirt simple), do a complete port and polish on your heads and TPI system (time consuming but free), and with what's left get a set of used Flowtech headers and U-bent sections of pipe and weld your own Y-pipe up (relatively inexpensive). After tuning, you can expect around the 300 rwhp you were after, and Megasquirt gives you the ability to go with forced induction down the road if you so choose. If you need a base tune to start from, there are tons of people on the Megasquirt forums that can help you, and it's all free. An MS-1 assembled and ready to go is about $350, an MS-II (which supports spark control, factory idle air, has a built in 4-bar MAP sensor for boosted applications, and as well as a more accurate AFR table) is about $450. MS-1 can also be upgraded later to MS-II standard with the daughter card for about $80. There's tons of info out there on Megasquirt, and lots of support.
I'm running MS-1 on a 4-bolt roller 333 ci modern 327, with a completely ported and polished TPI, milled 63cc heads modded for LT1 valve springs, LT4 Hot Cam, Accel 4-pin HEI triggered by a Mallory Hyfire 6A, custom '94 Camaro wiring harness, balanced bottom end, 11:1 compression, and 3" exhaust. I have a set of the Flowtech 2.5" collector shorty headers I'm building a Y-pipe for, and I'm getting ready to bolt in a built WC T-5 to replace my 700R4. Altogether I only have about $2500 in my engine, including the cost of the block, machining, parts, and my ECM. I make about 325 hp right now, and am getting 22 mpg with a worn out trans stuck in lockup and slips.

buzzthefuzz

Muffler already fell off, clamped $25 glasspack on, car sounds ok but it wont squeal the tires from a dead stop anymore. From what ive heard this is because the torque peaks higher in the powerband now. Whatever. So $1000 cant get me a cam or a bigger intake? Damn. Btw i never tried to suggest $1000 would get me 300hp, i just keep trying to find a way to get help with basic 305 mods but ppl seem more interested in shooting me down.

hondamaniac

iTrader: (2)

Thats the 1 reason it doesn't even pay to post on here, just look around. You either get people like that or telling you to use the search function. Most of the time there are a very select few who are here to help. By the way......welcome to the wonderful world of TGO

buzzthefuzz

1983chimaera thanks now i have something to go off of. I knew there had to be somebody with something useful to say lol

InfernalVortex

iTrader: (4)

The biggest bottlenecks in the chain for the LB9 is the exhaust, the camshaft and the intake. If you have the ability to put a cam in yourself, that's a possibility, but it's a very labor intensive process and you need to know what you're doing to make it work. You also have a flat tappet cam, which adds an extra element of concern to doing it properly because it will unravel on you quickly.

The tuned port intake is what it is. You can easily spend $1000 just on replacing little things on it, and you still wont see much of a gain.

And replacing any intake parts or camshaft is a waste of time unless you put a decent exhaust on it. You dont take a completely stock car, and just throw a camshaft in it and call it a day. There are significant tradeoffs that come with a different cam, and for it to be worth you need to optimize everything else in the chain, and optimize certain other things to match the camshaft.

And the LT1 cam or LT4 hotcam will not work in your car because it's not a roller block. I'd be shocked if changing to a new computer, with no other hardware changes, makes any difference whatsoever. The megasquirt is an excellent piece of hardware, but I question the logic of throwing it on a stock engine with a stock intake etc.

There are ways to make a 305 quick, but you need to change everything else in the car to make it work for you, and you need to be ready to sacrifice drivability. The other issue is to make that much horsepower from a 305 you will need to spin it pretty high, probably 6500 RPMs or so, which just isnt going to work with any kind of tuned port intake and is fairly risky on a stock bottom end to begin with.

So to reiterate:

1. You only have $1000 for the engine, what should you do? GOOD headers and exhaust. The price difference just isnt that much, and you need all the help you can get to get a decent return for your money. Go with Hooker 2055's out of the gate and a 3 inch exhaust and you'll be in pretty good shape. Even if you go to a 350 later, or a 383, or whatever, the 2055's plus decent catback will always be a good setup.

2. You want 300hp? This is how you do it, copied straight from a guy who did 12 second quarter miles on a 305, right around 300hp
- Ditch the Tuned port injection, get a Holley 4150DP and Performer RPM intake and get an old school HEI distributor, do the conversion
- Install some 3.73 rear gears in a working posi carrier
- Get quality stall converter. 3000-4000 RPM range probably
- get a Comp 280H camshaft
- do some bowl blending and pocket porting on your heads. Shave them down a few cc's for more compression, run a thin gasket
-run your 2055's + 3 inch exhaust system or run a custom y-pipe with some Hedman long tubes. Long tubes are cheaper, but requires you to custom fabricate it.

http://www.youtube.com/watch?v=_93-ig9Wvj4

But I will tell you, driving around the high strung big cammed carbed 305 on the street is a lesson in patience. It can be done, but it's not nearly as pleasant as just driving around a stock car. That whole car was built around using a big cam, and beating the snot out of the little 305 to make that cam work.

There's no magic bullet intake(or any other part) to instantly give you another 50-100hp. These kinds of things just dont work that way. You do exhaust first, then intake, heads, and cam. You throw a camshaft in it and it will run like poop because the TPI is done at 4500 RPMs and you need to spin it 6500 to see the full powerband. The car will run terrible below 1500 RPMs so you need a big stall and short gears just to get around in it. Thats what it takes to hit 300hp in a 305, and that's why people always suggest that if you want serious power, go for a bigger engine.

The only other solution is to get your hands dirty with a turbo setup. For $2000-$3500 plus a lot of welding and fabrication, you can actually get a decent turbo setup done for that car. Just be ready to learn to tune it properly. Turbo will get you WAY beyond the 300hp mark. The only concern about that is combined with the flat tappet cam's need for special oil additives, and the turbo's need for oil, I'd be a little worried about reliability, especially if you run high quality synthetic to help the turbo. The old flat tappet cams just dont like new oils. Would be a great idea to spend the $750+ to convert to a roller cam at that point so taht you can run a quality synthetic motor oil.

1983Chimaera

That's because people tend to spend lots of money on shiny go-fast parts without properly matching it to their engine. That's also why I said to simply port and polish his existing intake, something that will cost him dremel materials at most.

I believe I mentioned putting Flowtech shorty headers and a custom Y-pipe on the car?

The block can easily be adapted for the roller lifter spider, and the necessary parts can be sourced from most junkyards for cheap. As for the Megasquirt (or ANY programmable aftermarket ECM for that matter) it allows far more potential from the engine to be released, and for changes beyond the capabilities of the stock ECM to adapt to. Not to mention if he stays with a flat tappet setup, he can get a cam and lifter set for relatively cheap that will far outstrip the profile of his stock cam. I also didn't say anything about imply putting a Megaquirt in place of the stock ECM on a stock engine.

Not sure why everyone is so frothing at the mouth with the false gospel of power limited 305's. A 305 has less airflow than a 350, yes, but it can make decent power just the same, and it does not have to be spun into high rpms to do so. 300 is simply NOT an unreasonable number for a 305 to reach. If he has a TPI motor wit hstock heads, he should have 58cc combustion chambers and ample material to remove with porting, room for 1.94 valves if he so desires, and with the proper cam, intake, and exhaust mods such as I have outlined, he can feed plenty of air thru even a tiny 305. If he simply port matches and polishes his intake runners, he may even gain from the velocity of the air over going for huge volume, which on a smaller displacement can actually be a detriment.

Waste of money. More shiny go fast parts with an expensive brand name.

What you described I wouldn't even call a streetable car. Telling him to do the same is just ludicrous. A 3000-4000 stall converter on a street car is just moronic.

Not sure where you get the idea that rear end gearing has ANYTHING to do with how much hp the car makes...They only translate the power made by the powerplant to the ground, they don't add to it. Also, the TPI in stock form feeds air to 5200 rpm, not 4500. With a properly matched cam he can stay well within his ported and polished TPI's ability to feed air to the engine, especially with the smaller displacement.

Don't know where you get your price numbers, but they definitely are not real-world. Most of the later small blocks already had the bosses for the roller spider, and if not the conversion can be done at home. For that matter, for under $200 he can simply source an '87-up roller block, much less spend anywhere near what you claim a conversion costs.

Once again, I suggest cleaning up the airflow thru the engine, both intake and exhaust, as the factory castings are notoriously full of slag and detrimental to smooth airflow. Source some used headers (no need to spend more than necessary, it's not like they have moving parts to wear out). So long as they aren't beat to hell or rusted out, by all means use them! Replace the factory ECM (ESPECIALLY a magically craptastical '85-'86 TPI ECM) with something that allows you to tune the motor to it's maximum potential. Even if you upgraded to a stock '87-'89 MAF TPI ECM would be an improvement over the '85-'86 ECM. Use whatever rear end gearing you are happy with...If it's a daily driver, use higher gearing for better fuel economy. If you want a street/strip car, use 3.23 or 3.55's. If you want a drag car, use 3.73 or better, but kiss driveability and economy goodbye. The stall should be selected by contacting a company specializing in them once you have the final engine specs and rear ratio selected. They will take all your info and determine the PROPER stall for your car's output, desired performance, and driveability. Any idiot can throw a huge stall on his car...That doesn't mean he's using the right one. a lot of companies will even build you a custom stall if you like. NEVER just go with whatever some guy on a forum says (Even me!!! - DO YOUR OWN RESEARCH AND TRUST NO ONE! -)

Sojer

I'm like most hated on here with my 305. Like said 1k won't get u know where. But to keep the cost down look in the classified ads live on it u can find great deals on there ebay too. First get comp cam kit, ask them what cam is best for u (200) aftmrk base used (250) headers shorties and y pipe (200) spend the rest on tune and tune up. rebuild the tpi clean it, new gaskets,ect. U my not be 300rwhp but close to 300 fwhp. U prob don't have a hyd rollor block so LT4 can could work but would cost u every bit of 1k to put it in or u can buy my 305 in 2years I would say 1800 for it lol. Ppl will say 350 over 305 because a 305 has a long stroke and small bore. Long stroke means it can't rev fast to get u high HP small bore means u can't ge heads to feed high HP and its a small motor so not a lot of torque so u are left with is nothing. But most ppl are not making much power any ways so a mild 305 can sneak up on a few truck swapped 350s with intake and carb. 1 last thing u could spend 500 and get a nos kit 100 shot. Drive safe

InfernalVortex

iTrader: (4)

You make a lot of good points, but I have counterpoints I'd like to throw by you. It's the inability of TPI to breathe at high RPM's that will hurt a high horsepower 305. If you can fix that by siamesing the runners, and then get it to flow much better, the TPI will work. But that requires a lot of specialized work he may or may not be capable of doing.


Flowtech headers are pretty garbage, just a step above manifolds. Are they better? Definitely, but I dont consider spending money on some high end headers to be a bad investment, especially when it comes to the Hookers which have the best y-pipe around unless you wanna spend money on dyno don's stuff. If he ever moves on to a decent 383 later, the 2055's and decent y-pipe wont be as good as long tubes and duals, but if you need the practicality of shorties (most of us do), it's one of the best options out there regardless of cubic inches. Flowtechs will need to be replaced if he ever builds a serious engine later on. Then it's money down the drain. The 2055's are the last headers he will ever need to buy if he stays with a Gen I sbc.

You said you made a custom y-pipe. If he can build custom exhaust setups (He has shown no indication he can, but that doesnt mean anything) then it's a different ball game entirely. If you can make a custom y-pipe going with the cheapie hedman long tubes isnt a bad idea. Still there are issues with trying to get it under the crossmember, but a dual 2.5 inch setup with a simple h-pipe and some flowmasters will tuck up relatively well, and outperform the flowtechs by a huge margin.


With the 86 peanut cam, there just isnt much more potential there. The megasquirt is an excellent product, but I think that money would be better spent learning to tune the stock ECM. For a mostly stock engine, I dont see a megasquirt really making a huge difference. If he plans to go with some big mods down the road and he knows how to tune a car, then I'd consider it. Just depends on how far he wants to go with it. You're not wrong, I just dont like to overestimate people's ambitions and/or skill levels.

There are still a lot of considerations that need to be taken into account. A cam swap is the last thing I'd want anyone who is inexperienced with in-depth motor work to be doing. Even so, with the way modern oils are, I'd hesitate to recomend a flat tappet cam to anyone. You really need to set the valvetrain up perfectly to make sure there are no problems. For the work involved, to get a big return out of a cam swap is difficult with a TPI setup that chokes the engine at 4500-5000 RPMs. To make big power with a 305 you have to spin it up. Otherwise he's just gonna end up $400-$700 in the hole for expenses for the sake of 20hp and less long-term reliability. Again, you're not wrong, but it takes a lot of foresight, experience, knowledge, ability, and tools to properly pull off a cam swap, and in my opinion to swap to a cam that plays nice with the TPI wont net you enough of a gain to be worth the trouble. Bets are off if he has the knowledge/ability to port/siamese a TPI system... but again, I dont like to assume that sort of thing.

Well that's kind of the issue. TPI heads are okay, but not amazing. To make big power you either need amazing volumetric efficiency, or you need lots of RPMs. He doesnt have $1500 for some amazing aluminum heads. So he's stuck with just tossing a big cam and spinning it to the moon to make it work. The TPI will choke it long before that strategy will work. It's just physics, torque is produced by amount of air+fuel burning. Horsepower is torque multiplied by RPMs. You cant increase the amount of air without increasing the cam size AND the airflow independent of valve timing. The problem is that you cant increase the amount of air going through the TPI and the 081 heads significantly without increasing the valve duration also shifts up the powerband beyond what the TPI will support. Of course you can increase the displacement to increase the volumetric efficiency, but its not easy to make the 305 a 383. So if the volumetric efficiency is static, the only way to get more power is to just spin the thing harder and put a bigger cam in it.


To summarize... I DO think 300hp is unreasonable from a factory heads and bottom end 305. My buddy's 305 I mentioned earlier trapped 104-107 mph in a 2900-3200lb car depending on the level of mods/weight reduction it was at over the years. Depending on your maths (Adding a driver) it ranged between 300-340hp over the years. That was with a Comp 280H, ported 416 heads(the same ports as the 081 heads that he has), Holley Street Dominator intake, and a Holley DP with a 10.2:1 305. And you already told me you didnt that car was streetable at all.

To be clear, I dont think it's streetable either, but it was his daily driver like that for years. The point I was making is that 300hp from a 305 requires some serious work and sacrificing a lot of low end torque, the TPI setup, and spinning it to 6500 RPMs regularly. It's just math. Smaller cubic inch motors have to spin faster to make the same power as larger ones. The worse the volumetric efficiency the more true that is.

Also, I think you can hit 300hp much easier with a big roller cam with a 305. I think some mildly worked heads, siamesed/ported TPI, megasquirt, and an LT4 hotcam can probably do it. If you're talking about a street car, the durations you can work with are limited so the ability to use a roller cam to get those valve lifts sky high and get those ramp rates up helps a LOT to get the power levels up and keep the power band a little more reasonable. I think you're still looking at about a 2000-6000 RPM range you're operating in, which is still way too high for a stock TPI, stall converter, or gearing to be happy. But after you set up the car for the cam, it actually could be somewhat streetable at the 300hp level. I think a Comp XR270 could get you close, and an XR276 could hit it and maybe surpass it.


To make 300hp with a 305 and stock heads, you HAVE to shift up the powerband significantly. The gears facilitate this and make it drivable. A loose torque converter helps too, but the rear gears will make a big difference in how streetable it is. I agree it has no effect on power, but it facilitates larger cams and that makes more power.

Again, you're not wrong, but Im not going to assume he's ready to just buy another block. That's a BIG undertaking to build a new engine, at that point he may as well just buy a 350 core, it'd be a waste to buy a 305 core, I gave mine away for free years ago and it ran perfectly when I pulled it. That said, if you meant to spend $200 and buy a core to use it for lifters/roller hardware, that's an interesting angle, but you can actually get the factory hardware and lifters for a lower price online without too much trouble.

Unfortunately that's not an option for him. An 86 305 is a flat tappet block and will MOST likely not have the bosses for any of the roller stuff. That means $300+ lifters, $250-$350+ for a retro roller cam. Plus decent valvesprings, and pushrods and you're at $700 minimum. You cant use a cheaper used factory roller cam because you have to use a cam button, and the factory roller cam snouts have the timing chain bolts so close together that you cant really get a cam button on one, it's possible, but you have to force a square peg into a round hole to do it. The factory roller cam retainer bosses aren't going to be on his block if it's a stock 86 block, so a cam button is necessary.

You do make a great point about the 85-86 ECM, I forgot that they changed that. Makes a megasquirt make more sense, but you can go a long way with the stock ECM, and even farther with a 7747 that can be had for pocket change in a junkyard. Im still not quite convinced it's the best way to spend $200 of a $1000 budget, but it's definitely not a bad purchase especially long term.

Also, my buddy with that ridiculously unstreetable car you were talking about earlier... he got over 20mpg with it... and that was with 3.73's and maybe even 4.10's. He even had 4.55's in it at one point, but I cant remember which gearing got him that decent gas mileage.

Im not trying to crush anyone's dreams here, but Im just saying it's tough to make a 305 put out respectable numbers. I dont want anyone pouring a ton of money into a 305 that wont get them out of the 14's.

Street Lethal

iTrader: (16)

If you can do your own porting, and if you know how to weld, then 300-RWHP will essentially be very easy to reach with a turbo charger for very cheap...

1983Chimaera

The TPI in STOCK form can feed the L98 with its 350 ci and larger cam profile up to 5200 rpm. A ported/polished TPI and heads will have no problem feeding a cammed 305.

You keep trying to sell him on one particular go-fast part...Do you WORK for Hooker?? Are you on commission? And doesn't Flowtech MAKE the Hooker headers? They ARE both owned by Holley...

Even the used Flowtechs (and I use those only as an example because they are the same as the Summit shorties, some of the lowest price headers available, they DO offer significant flow over stock manifolds, and because of people like yourself that only believe power comes from spending obscene amounts of money are relatively easy to find secondhand for cheap) are an improvement over no headers at all. And simple welding, a hacksaw, and the ability to read a tape measure, and some pre-bent U aluminized U pipe are all that's needed to build a Y-pipe. I like to give the poster just a LITTLE benefit of the doubt.


At no time (I can't believe I'm having to state this a second time!) did I EVER say to put a Megasquirt on a stock engine, or say to retain the peanut cam. READ MY ORIGINAL POST. I offer Megasquirt as a way to compensate and effectively fine tune for the changes I suggested, well beyond the capabilities of any of the available factory ECMs, and more reliably than chip burning. I also in my original post believe I pointed the poster to the freely available support that exists in the multitudes on the Megaquirt forums. I got my base tune from said forums, a factory Formula Firebird 350 base tune that I played with and tweaked until I had my AFR table correct. All without the benefit of a dyno, wideband O2 sensor, or professional help. It's simply NOT that hard if you take your time and do your homework, which I why I believe the poster has the ability to also accomplish this. Again, I put a little faith in the guy.

What cam swaps have you done?? I pulled an LT1 cam from the junkyard out of a Caprice Classic, and it took 20 minutes. Cam swaps are NOT exactly rocket surgery or brain science. If he's going to have the engine apart, it will be dirt simple. As long as he does his homework, he will have no problems finding a cam that meets his desires and plays nice within the abilities of his MODIFIED TPI system. Or are you assuming it takes a PhD to operate a Dremel?

The factory 58cc heads WILL support what you're trying to do, this is the part where a lot of people on this forum will try to quote math they have no actual support for. The 58cc TPI head is just a iron version of the Corvette TPI head. With basic porting and polishing to smooth the airflow and port match the intake runner opening to the TPI base (nice, smooth transitions is what you want), open up the exhaust the same way, use the gaskets as a guide for what you need to remove, and you will increase the ability of the head to move air thru. If you so desire, the heads also have the ability to fit larger 1.94 valves (I have a set of these heads on my bench right now and tested just that last night, there's PLENTY of room), and you can also upgrade to 1.6" rockers and a set of springs to handle the extra lift. The 58cc's make for a nice high compression, and the smaller smoothed out intake runners keep port velocities higher, which on a smaller displacement is key to making power.

Siamesing the runners is for larger displacements, not smaller ones. This would be counterproductive.

And chirps the tires constantly, will constantly be slipping the stall in and out of hydraulic lock on the highway, and probably be a ticket magnet for "Exhibition of Acceleration". You're assuming (You really do that a lot) that he wants to build a quarter mile car. He only said he wants 300rwp or close. Gearing has NOTHING to do with that.

My friend and I built a hypothetical 305 last night using Comp Cams Dynotune program, using a 305 roller bottom end, 3500 lb car weight, 221 / 225 @.050 and .485 / .495 profile cam, stock TPI with 750 cfm airflow, pocket ported wedge heads, 9.5:1 compression, and made 299.1 hp @ 5000 rpm and 347 lb ft @ 3000. Past dyno results from Car Craft and Hot Rod have confirmed the accuracy (if anything on the CONSERVATIVE side) of the Dynotune program. So no, you don't "spin a 305 to the moon" to make big power. The TPI makes bottom end torque, that is why it has the long runner design in the first place, which (here's that math thing again) means that since hp is a FUNCTION of torque, the lower the rpm where peak torque is reached, the lower the rpm where peak hp is reached.

I only suggested pulling a junkyard spider assembly, NOT buying a block just for those parts. For someone that claims to not like to make assumptions, you sure make a lot them, and BAD ones at that. An '86 flat tappet SHOULD have the bosses for the assembly, depending on the manufacturing plant and date code. If not drilling and tapping the block is not a huge undertaking.

Depends on the factory, and the date code on the block. Most roller cam parts can be sourced from the junkyard, which unlike their flat tappet counterparts CAN be re-used safely.



This is my last post on this thread as I'm NOT looking for a flame war. To the OP; I've given you starting points to do your homework on, and what has worked personally for me in my builds, NOT secondhand knowledge or "I once knew a guy"... I'm currently rebuilding an '88 IROC-Z LB9, and speak from experience on my 327 build and numerous other engines. Again however, only use forum posts as a starting point, NOT as gospel. Do your own research, form your own opinion, and plan everything out before you buy part ONE. This will save you tons of hassle and money down the line, and make the end result that much better.

Street Lethal

iTrader: (16)

No, it is not. Siamesing the runners will give him only a limited amount of RPM to play around with because all it is doing is essentially creating a more linear/shorter/direct path from the plenum to the cylinder heads, that is all that it is doing. The intake charge is still being pulled through twin 48mm throttle plates, regardless if the runners are siamesed or not. That does not change. The only counterproductive concept on smaller displaced engines is either adding too large of a carburetor, or in this case, too large of a throttle body, as a 58mm throttle body defeats the purpose. Siamesing the runners while maintaining the stock 48mm throttle body will only increase velocity, something that he wants...

erik69&85

iTrader: (1)

Back in March of 1999, Car Craft ran an article about how to get 325hp out of a 305 with bolt ons. I found a print out of it in my files. I thought I got it from TGO a number of years ago. Maybe you can still search around and find it.

In short, it used an aftermarket intake, carb setup, upgraded heads, and a hotter cam. Didn't use the LB9 intake setup....still worth looking at to see what they did to get to 325 bhp.

hondamaniac

iTrader: (2)

This isn't the car craft article but it is similar.

http://www.popularhotrodding.com/eng...s/viewall.html

buzzthefuzz

so all disagreements and naysayers aside, im really glad i started this thread, it seems to have taken on a mind of its own, but it was to my benefit... im definitely going to be looking back through this all the time. thanks to all for your input, and remember... "America! F**k yeah!"
sorry, i had to put something in there to create some unity.

if anybody has a good cheap way to stop my car from rusting away pm me, not sure if im going to grind it out then primer it or what, but its gotten a lot worse since i moved right next to the ocean. i recently found some pretty large holes in my trunk right where the ground effects are, and in quite a few other places too. im scared.

InfernalVortex

iTrader: (4)

Ive attached a dyno sheet from a factory TPI engine dyno test. After about 4500 RPm it's done. Maybe it will go to 5k on a 305, that's still just not turning fast enough with the available torque of a 305 to hit the kind of horsepower goals we are talking about.

I think it's smart to buy good headers once, instead of buying crappy headers, and later upgrading. Depends on his ambitions. But to hit 300hp with a 305 he will need all the help he can get. Flowtechs will leave power on the table.

I run Hedman long tubes that I got for $100 with the paint still on them. No regrets, love that setup. If you are on a budget and want power AND can fabricate an exhaust, then I think the Hedman long tubes (68460) are a much better option than flowtechs - larger primaries, longer primaries to build more low end torque (will help because you will need to overcam it to hit 300hp) and a simple dual 2.5 system with an H-pipe will give enough ground clearance and make more power than a 3 inch single with a factory route y-pipe in front of it. If you want pics of my setup, here it is:



I just believe in doing exhaust right the first time, because exhaust sets the groundwork to get more hp per $$$ for every mod you make after that. I'm fine with you disagreeing and saying flowtechs are a better option for the money, but there is logic in what I am saying.

Same applies to Hedman 68460's. If you are willing to deal with ground clearance, they are the best cheap option, and that's the route I went.

Bolting it in is easy. The hard part is making sure the valvetrain is set up properly. Things like valve guide to retainer clearance, spring selection, coil bind height, spring installed height, open pressure, closed pressure, pushrod length, rocker arm choice, screw in or press in or pinned studs, etc becomes absolutely essential to do properly with a LOT of attention to detail with real performance cams, and that's what a 305 will need to hit this power/RPM level. A 90s caprice cam is NOT a performance cam.

A factory B-Body LT1 cam is 191/196 0.418/0.430 lift 111 LSA. This is absurdly tiny in even the factory cam world, and nowhere near enough to hit the power goals he's talking about. You start approaching .500 lift and 220s-230s in duration like he needs to and you need pay a lot more attention to detail on setup.

The Corvette TPI head isnt that great. Neither is the factory 081 or the 416. they all share the same port design. It's much better than anything that came before, and it will support the power levels we are talking about especially with some minor port work, but you will still need to cam it up to hit those power levels. My buddy's 416s had exactly the kind of work you're talking about, and he still needed a big 230/230 .480/.480 cam with tons of efficiency mods, perfect exhaust, etc, to hit the power levels he did. Throwing in a grocery getter cam from the 90s and some flowtechs are not going to get there.

Not at all, you will HAVE to spin to 6000+ RPM to hit 300hp with a 305 with even perfectly ported heads. There's just nowhere near enough air drawn in each stroke to hit the power levels you're talking about without upping the RPM's. That means anything you can do to increase the TPI's operating range will help. Otherwise you'll end up with a car that pulls hard from 2000-4500 RPMs and fall off a cliff. No sense in camming up and not benefitting from the increased peak power you get by extending the power band out.

300rwhp is impossible with a 305. I've been talking flywheel horsepower this WHOLE time. Just give up on that notion. ANy of these mag dyno tests hitting 300+ hp, they're not even turning their own accessories. They're running through huge long tubes with single plane intakes and big holleys on top. Add in a restrictive factory style exhaust system with flowtech headers, alternators, power steering pumps, water pumps, smog pumps, air conditioning, and TPI intake, and you're just not going to get the same results. Compare SAE net vs SAE gross horsepower ratings, and you'll see how big of a difference the testing methodology makes. Remember, factory horsepower ratings are fwhp(with accessories and factory exhaust/intake). So an L98 making the factory 245hp is only making 210hp to the wheels. And you want to increase rwhp over an L98 by 100 hp with a 305... the odds are already stacked against you.

About making assumptions, I assume he doenst have the ability to port, to fabricate, and do in depth engine work because he seems like he doesn't know where to start to get to his power goal. People with a lot of mechanical knowledge and tools accumulate it over time with experience and research, and likely wouldn't need to ask these kinds of questions. If someone is comfortable with porting, they'rej ust going to take it apart and start porting things. There's nothing at all wrong with needing to learn this stuff and not being able to do it, we all start somewhere, but telling him to jump in with a die grinder to the engine internals of his new car isn't something Im going to endorse right off the bat.

But lets go back to assuming fwhp. To hit 300 fwhp the 305 will need to go to 6000+ RPMs and ignoring the fact that the factory rod bolts cant handle that, that will mean that the cam necessary to do it, will not be able to make power until, at the earliest, around 2000 RPMs. Trying to drive that around with highway gears and a stock torque converter will make him hate driving the car. It will just be a dog. The converter is necessary to make the car at all drivable, and the gears are necessary to help the converter and engine get teh car rolling from a stop. It's not about quarter miling, it's about just being able to drive a 300fwhp 305. It's not nearly as easy as you think it is. Most bolt on even modded L98s and custom built 350s with factory heads and carbs are barely at 300fwhp, and they dont have nearly the same restrictions and bottlenecks a 305 is going to have. A vortec headed 350 with a big roller cam is gonna be able to hit 350-375fwhp if set up very well. Make that a flat tappet, and you're down to 325-350. Make that 083 heads (same port design as 081s, but with larger valves) and a flat tappet, and you're down to 275-300. Take away 45 cubic inches, insert a larger valve, and add a high RPM restriction intake... and there's just not much room there without sacrificing a lot of the streetability you seem to think you can keep. 250fwhp is a lot more reasonable goal from a 305 LB9.

I dont know enough about the program to know how it handles all the variables. Do you know if it counts for parasitic loss of the drivetrain/transmission? Does it count accessories? What exhaust is it assuming? Probably not flowtechs... I dont think that's too far off, but Im not sure a TPI could hit a peak hp at 5000 RPM. It may with a 305, though. It actually sounds pretty accurate for fwhp with a roller cam. I already mentioned that was probably achievable if you were able to do the necessary porting, exhaust, and computer work. Remember my xr270/xr276 comment? The smaller xr270 is 218/224@.050 and .495/.502 lift. The larger xr276 is 224/230@.050 and .502/.510, so your cam is right in the middle, and right in my projected range I listed. The smaller xr270 (barely smaller than your cam in duration) has a power band of 1600-5400. Those numbers assume a 350 cubic inch engine. With a 305 (due to the nature of displacement, torque, and airflow), that power band will scoot up at least a couple hundred RPMs. I would assume around 1800-5700 RPMs for the smaller cam, and 2000+ for the larger. With the roller cams you wont need to spin it quite so high to hit the horsepower numbers you want, but it will still need a stall and gears to get it around easily.

Beyond that, as we all know, he has an 86 car, and if the engine is stock he is limited to flat tappet cams with an 86 block unless he wants to convert to a roller cam(which is a great investment, I think). So trying to hit those power numbers with a flat tappet cam will get tricky. He will probably need an xe268 or 280H to do it. The xe268 will have a power band of probably about 2000-6000 on a 305. The 280H a notch higher. The hp peak will happen around 5500 or so on a 305, beyond what the TPI is going to support without mods.

That is exactly the problem. The TPI makes bottom end torque. Torque x RPM = horsepower. The TPI is useless above 5000 RPMs, so whatever torque you're making at the upper RPM limit of what the TPI can handle, assume 5000, that times the RPM is all the horsepower you're going to be able to make. Torque is finite and a function of how much air/fuel can get into the engine each cycle. Basically a function of volumetric efficiency times displacement. You will not be able to change that significantly enough with factory heads to hit 300fwhp without going over 5000 RPMs. You will likely need to go to 5500-6500 with a flat tappet cam to hit that horsepower level.

If it does have the bosses, it likely still wont be machined for the dogbones. There are differences in the lifter valley even on the 1 pc RMS blocks that are flat tappet blocks, and it may be fixable, but Im not sure. I've never actually tried it. But the surface the dogbones sit on is machined from the factory so that they fit snug and to keep them flat with relation to the lifter so they dont bind. However, even if that's the case, he can drill/tap the timing chain area and use a factory style cam retainer, and he can go find a used LT4 hotcam somewhere (I think it'd be the best bet. Not sure how much power it will really make, but I would imagine the 275fwhp neighborhood) and have a pretty stout setup assuming he can get all the supporting mods in order. I still dont think that he will be able to use a factory spider/dogbone setup, but it may work. I would be leery of trying it after seeing the differences, but I've never been able to actually set them in place back to back see if there's a difference in stability. But it would make me nervous in an engine you will want to spin to (since a roller cam, 5500 is about the ceiling, and a lot closer to what you can set up a TPI to handle with a 305) 5500 RPMs to have those in there if they arent snugly in place.

Here's an example with a 383 with a fairly large xr276 hitting some decent mpg numbers:
https://www.thirdgen.org/forums/carb...le-pumper.html

A 305 with similar cam hitting those numbers isn't unreasonable. It just requires a good tune.

The difference between you and me is I've shown you nothing but respect the whole time. I just think 300fwhp from a 305 will lead to disappointment and a lot of wasted money. There are ways to do it, but people need to understand that it will be either barely streetable or expensive, and I'd rather people make informed decisions than emotional ones.

InfernalVortex

iTrader: (4)

Best thing to do is fine another shell and move all the parts over if it's REALLY bad. If it's in decent shape otherwise, it's not a bad option. You'll learn a LOT by doing that too. A lot of people would say to part out the good stuff and buy another car with the proceeds. You would be amazed at how much money you can make parting out an IROC that's in bad shape, much less one in decent shape. And dont think of it like you're destroying a car, you're parting it so that other cars can survive.

Otherwise, if the rust is limited to floor pans, trunk pans, etc, things you can easily cut out and reweld, I wouldnt sweat it too much, Just be sure to check the WHOLE car thoroughly. Check the floorboards, the firewall, the rocker panel areas, etc.

You can save anything with enough welding and cutting and another shell to cut parts from, but it's up to you to decide how far gone it is and decide whether you want to cut up another car to fix panels with bad rust, or just move all your good stuff over to another car.

lettuce

iTrader: (1)

Good question, buzzthfuzz. I have an 86 iroc and I wanna make it bit quicker too. I don't think it will be a gem of a car someday but I don't wanna tear it apart to build a better car. Thats what berlinettas and Rallysports are for. I just figure mechanics and enthusists have found ways to make these motors a bit better without tearing them out. This thread has left me confused, I think.

GVMV

iTrader: (2)

I don't think anyone mentioned. If they did I am sorry, but a lot of repeat information in these posts and I get tired of reading it.

Another option to make the car quicker depending on what you have in there now. Some cars game with 2.73 or 2.92 rear gear (yes even in z28 and TA's) . Easy to find a 3d gen rear end for cheap or go 4th gen (but 4th gen is slightly wider) that has 3.23 or 3.42. This would make the car quicker off the line with what power it has. Of course you are going to sacrifice some mileage.


On your rusting issue I would get so POR-15.