paulmon

I've read the various "banned topics" threads, but for the most part are still left scratching my head. I'm a complete idiot as far as the 305 is concerned, no experience with it at all and not much with SBC in general.

I'm building a Lotus 7 kit, and was originally going to use an LT1 I had found but that deal fell through, not to mention the T56 tranny is damn expensive. I've now got a lead on a 5-speed 87 TPI from a Firebird GTA. As starters the car will have a "cold air" intake, custom headers, custom exhaust, these are required to get it to fit into the car. Oh, and no emissions gear as the car doesn't need to meet emissions as a kit car.

The engine itself is bone stock, so aside from those pieces, and keeping in mind reasonable $$$, I'm looking for suggestions on "next steps." Effectively as the "banned topics" thread suggests, intake base, cam, and heads are what I'm looking to do. I'm looking for higher RPM power rather than tree pulling torque. Obviously budget is a concern I've got around $1000 to "refresh" this engine. So with that budget I might not get everything I want first time around. What I don't know is who makes the various parts for these engines and what I should watch out for. Seems most of the aftermarket focuses on the 350.

So I'm not sure who makes an intake base for example for this engine and which one works well.

As for cam, obviously I want someone that will work with the head. That said companies like Edelbrock and others seem to have heads for the 302, 350+ but no mention of the 305. So what head choices are there? I don't have any issue running higher octane pump gas with the engine so compression ratio etc are all on the table modification wise.

Finally cam, I don't care much about 100% "streetability" of the engine, it's effectively going to be a Sunday driver and spend 90% of the life at the track road racing.

What about other things like pistons? ECM programming?

So suggests on where to start?

Thanks again and sorry for such a newbie set of questions.

For those not familiar with the Lotus 7/Locost, here's a pic of the type of car I'm building (mine will have a full cage however), my blog can be found at http://www.brutusv8.com/ car will weigh in at 1600lbs and I'd like to squeeze 300hp out of the 305.



Paul

vipershark11

iTrader: (6)

the tpi isnt meant for high revving nor will you get it to rev really high with mods maybe a little higher than stock. as for 300hp youd need heads,cam combo that works well and maybe port the tpi setup. seeing as you only have 1k to spend best off getting a computer friendly cam zz4 maybe and forget aftermarket heads. you can port the 081s and get those fixed up and be in good shape. just make sure you run it with the MAF sensor thats on the car youre getting.

paulmon

Yeah, I've been doing a bunch more reading and see that TPI doesn't give much in the way of top end power. So be it.

Thanks for the tips.

Paul

bigtgun3

Im in the same hole as you man.My thought is to just get a 350 tpi eng or if you dont want to deal with the tpi sytem then just got with a 350 and work with a carb setup if you dont want to deal with the bay cluter

subroc

iTrader: (2)

Ill tell u my combo which is putting 216-220 at the wheels (wasnt running the best for the dyno run so it had more in it). Its a 305 with a LT4 cam (zz4?), AS&M runners, Edelbrock base, ported plenum, Edelbrock shorty headers, and a 3 inch exhaust. Now if u add in a few more goodies like heads, roller rockers and a better tune than i have (tpis did the tune for the previous owner) you should be barking at 300hp. Oh yea my combo pulls all the way to 5000rpms where the original motor bone stock would die after 4k.

Shadygrady

iTrader: (3)

[QUOTE]I'd like to squeeze 300hp out of the 305[QUOTE]The power you want would be easier to get out of a 350.I t can be done with the 305 though.350`s are easy to find and can make more power easier.

Subroc do you have the LT4 or the (ZZ4?cam)I`ve never dynod mine but It feels like it pulls to 5000 rpm with the stock tpi Or atleast very close to it.Although I realize that is where the stock tpi limits are.Its nice to see about what you dynoed if that is the LT4 cam.I just picked up a tpis base off of ebay and was hoping it would pull to 5500 with ported plenum and aftermarket runners.Thats only 300 rpm`s off the LT4 peak HP rpm.I was hoping to get (thought I`d be lucky to get)300 hp at the flywheel out of my 350 with that cam.

subroc

iTrader: (2)

I was told by the previous owner it was an LT4 cam (not the hot cam). Thats different than the zz4 then right? that was why i had the question mark i wasnt sure.

As far as your 300hp at the flywheel with a 350 that is very doable IMO. I mean mine is only a 305 and im at 216 at the wheels which at the flywheel is what...250-260? Somewhere around there?

redliterunner

for a budget deal, and since emissions are no problem, I'd look at the LT1 intake converted for TPI use. Don't know the url, but its pretty easy to find via google. You solve all your bs TPI problems at once, and get more power potential up higher in the revs.

Oh yeah, its http://lt1intake.com

paulmon

wow, this is a pretty old post.

I bought an LT1 in the spring with T56 and used that. Drove the car for the first time a few weeks ago, BLINDINGLY FAST. http://www.brutusv8.com/ to see a video of one of my test runs.

Paul

8T9 BANDIT

open up the intake, do a cam. As long as its running efficently ie: good tune, sensors working properly, fuel and air mix is good. With that light of a car, that will be an animal, It probably wont hook up for sh*t, which i think is a good thing. a tuned port 350, may even be overkill in the tq department with that car. Either way a strong running lb9 in there, we be tons of fun im sure.

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wow, sorry, i didnt realize the post was so old, ignore what i said.

RockinIroc

While the old adage, "There's no replacement for displacement", is certainly very true, it's not always correct. Back when we were complaining about gas prices being almost $2 a gallon, and we really did have it better than now, a lot of people were building mountain motors, super strokers, and big blocks. Well, getting low-teens gas mileage (if you're lucky) gets old when gas is spiking over $4 a gallon. So now more than ever, a 305 build up makes sense.

Popular Hotrodding built up a 305 converted to carburetion (for the rpm advantage), a better Comp flat tappet hydraulic cam, and a good set of Vortec heads (real Vortec heads, the ones with the LT-1 style heart-shaped combustion chamber). Guess what they got? 372 hp.
You know what? To get 372 hp in a crate 350 from Summit, you have to spend some bucks. That's not bad out of a 305.

In fact, I've got a 283 motor that I'm running in a 3500 pound 1952 GMC pickup truck, which if anything, weighs more than a thirdgen F-body. It's got 3.50 gears on a Dana 60, and 10:1 compression. And that truck REALLY scoots. It'll beat almost any of these local hotrod trucks in a flat out drag race. More than enough power.

The TPI was a great idea. By using inertial supercharging, the midrange torque is fabulous. BUT it is limited in high rpm. Even with the bigger hogged out runners and TB that is available, you're still only going to manage about 5000 rpm. I did test drive one 5.0 liter TPI IROC-Z with a Paxton supercharger, and that engine did a good job. The blower pushed the limit up close to 6000 rpm, by force feeding it. So that's another option for you. I'd personally opt for a turbocharger, myself. Preferrably the one that replaces the muffler out back. (I forget who makes that).

The 305 that was in my IROC was rebuilt (by me) and sold to a guy who has it in a Ford Model A roadster now, and he absolutely LOVES that engine. So maybe there is a new purpose for the Mouse motor that everyone loves to hate.

Here's that article:
http://www.popularhotrodding.com/eng...s/viewall.html

Solders18

The turbos you are thinking about are made by sts turbos. They specialize in remote mounted turbos and replace the muffler(s)

Dakota W.

All you really need is a t56 and numerically higher rear end gears, that with headers and a port and polished plenum, runners, and base will get you a reasonable increase for 1k. I've seen T56 trannies for sale at $500, and a rear end can be had from a junk yard for less than $200. I'll tell you that you should expect to spend AT LEAST $2000 for cam, lifters, and valvetrain. That is of course if you get something worth buying.

Have you considered running a toyota 2jz? You don't need a V8 for a lotus and would gain more from a 6 cylinder's lightweight than a heavy 8 cylinder.

HowIroc97

I recently purchased an 85 iroc w/original motor and trans(5.0 tpi and 700r4,unsure of read end specs).I've decided to stay with original motor,now I'm seeking guidance on best performance upgrades(cam,headers,exhaust,heads,injectors,etc. Is the edelbrock hi-flo tpi kit worth buying?,what are some good upgrade to 700r trans?My personal research showed that my engines horsepower is rated at 215 and torque around 225. So to get those numbers around 350+ would be ideal. 2500 dollar budget(no spray,procharger,or turbo please)
Thanks

z28mr.bacon

Subroc is yours an automatic? Cus my lb9 5speed is stock and feels like it puts way more then that, it beats 300 hp cars

Heatzone25

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subroc

iTrader: (2)

It was once upon a time when i made this post lol. I ditched the 305/700 and built a 355 hi compression motor with a tko 5 speed. Now it moves.

jjcuff1

SO your syaing even with worked 305 a mild 355 built was still night and day

Orr89RocZ

iTrader: (20)

http://www.superchevy.com/technical/...d/viewall.html

vetteoz

iTrader: (13)

There is a general line of thought that you can only get so much out of a 305 ( streetable) and that starting with a larger engine results in a better bang for $$$
Do a search , a million 305 build posts on here

https://www.thirdgen.org/forums/post...576-post5.html
https://www.thirdgen.org/forums/post...864-post2.html
https://www.thirdgen.org/forums/post...51-post25.html

But there are options if you have $$$ to spend
http://www.popularhotrodding.com/eng...engine_blocks/

subroc

iTrader: (2)

Well idk if i would call it mild. Its not crazy but i did research and spent money in areas that were worth spending money on. It engine dyno'd at 406hp/415ftlbs with a holley carb and victor jr intake. I have not chassis dyno'd it yet to find out what it does now that its set up with my high flow tpi setup that was plucked from the 305.

Basically i wanted to take the car to the next level and to do that it was more economical to build a 350. You will end up spending the same amount of money to build either but if you want the 305 to run with the 350s you will end up spending more. Thats just my take on it. Others differ.

Dakota W.

To be honest with you, I think building a 305 is cheaper if you already have a good bottom end. I've spent far more than what I would've liked to on my 350 build, and for the same price or more, I could have a HOT 305. We're talking 305 that might blow main caps hot. And honestly, with the headache of the 350, I kind of wish I just rebuilt the 305.

Orr89RocZ

iTrader: (20)

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

And another.... High 300's hp with ok heads seems to be about all these motors are doing. Really need to up the cam to get them to make power but also need a great set of heads

Street Lethal

iTrader: (16)

Depends what you mean by worked 305, tremendous difference as far as "worked" 305's go from member to member...

jjcuff1

By worked I would mean stock ported heads and plenum, bigger cam, free mods exhaust stock tranny with shift and converter and street gear 3.40-3.70

I know a 350 is better for HP and cheaper from scratch. But if 305 works cheaper to mod it and hang witth STOCk cars on the street. mod for mod more cubes win or easier and cheaper for sure.

But just as a standalone car that you hop in fire up sounds like a v8 not a weak one or a v6 but an american v8, rumble, burly sound then step on it and can smoke and bark tires and pin you in the seat.

At a redlight it can catch many cars off guard at least from 1-2, 2-3 and let off so what it is the street. Sure most new v6 and up will walk away by 2-3 but i dont care. just a toy for me

So with that in mind if 305 is still good and for those that had both 305 then 355 was there a differance bwteen a mild or stock 350 swap tpi vs the 305 they probably dumped money into then blew it up or wanted more. was cost worth it vs a mild street 305?

Street Lethal

iTrader: (16)

You have a lot to learn still, horsepower is just a resistance measure, RPM is what matters, horsepower gives us our rate of acceleration, and any engine when built properly will get it done. Don't get caught up with the bigger is better, and/or cheaper mentality, because it costs everybody in the end...

Dakota W.

Throw the stock heads in a furnace, they're not worth anything even if you port them.

Orr89RocZ

iTrader: (20)

Mod for mod cubes win generally because other sbc's have bigger bores and can fit bigger valves which pass more air which can be used to make more hp. Hp wins races. 360 hp at 10000 rpm aint gonna move 3500 lbs any faster than 360 hp at 5000 when geared correctly for each

305 can be made pretty stout but never will match bigger bores because airflow isnt there in small valves. Only way a small valve will work in small bore is multiple valves or layed back valve angle like lsx motors... 18 , 15, 12 deg heads. That way you can jack up airspeed and remain laminar in flow to pass more mass of air. A 23 deg head is velocity limited, it will go turbulent sooner. Nobody makes 12-18 deg heads for 3.73" bores so you are screwed there. You need larger ports to turn more rpm to make the power in small cubes and you cant because you are still valve limited

jjcuff1

Great discussion thank you. I agree with the head and airflow talk of the 305. I think
1: I appreciate the lot to learn comment but I understand math and what power means work/sec (ie: the slope) The derivative of that is acceleration of the slope or the area under the curve and hence where I think you can see the difference between ford/chevy as example.

looking at a dyno peak HP like the old mustang 5.0 had it was at higher RPM and with mods and light weight of car was fast but the camaro was still in the mix or faster.It was the area under the curv´, the 2nd derivative of a HP curve.

So back to my point, I realize it is not a modded 350 VS a 305 mod, but on teh street for pure performance. the 081 heads are not worth modding with a cam to match?
money aside, I know I can swap parts to a 350 when needed. So...

better question what is a good head that maybe can work with a 305 and when ready for $$$ be swamped to a 350. That way I can tinker with 305 until I am ready to build bottom end

Street Lethal

iTrader: (16)

Win what? What exactly do they win? Show me a turbo SBC cubes w/the same mods run faster than this turbo six cylinder...



Really? I would say weight, gearing and RPM have just as much say. Considering Rob Mapps is only making 400-WHP and running nines naturally aspirated in his lightweight Honda, I would say HP doesn't always win races, and like I said, weight, gearing and RPM have just as much say. Let's see a 400-RWHP V8 "geared correctly" running naturally aspirated run nine seconds just like his Honda, will it? Can it? Maybe with a high revving 400RWHP 302 SBC it might be able to reach that ET, but not with just 400 rear wheel horsepower alone capped at a lower RPM of say 5500/6000-RPM. It takes x amount of horsepower, weight, gearing and RPM to run a number, and some lower the horsepower while improving the other three areas while achieving the same results. It is a careful balance of all four, not just one my friend. But like I said, if RPM is meaningless, then let us see a naturally aspirated SBC running in the nines at just 400-RWHP, and being geared correctly for a lower RPM...



When geared correctly for each? What the hell are you talking about, who in there right mind would gear a 10,000 RPM motor so that it can give a 5000 RPM motor a chance? The one who reaches the highest RPM and gets there first with the same final gear ratio wins the race, period. Horsepower is just a measure of that rate of acceleration. There is a reason why GTR's and Supra's own the track and the highway, and it is because of their RPM potential, not just horsepower. I can show you an Alpha 12 street GTR running in the sevens while screaming in their RPM band. You honestly think cutting that RPM in half while gearing it appropriately to compensate will net the very same results for the same car at 5000-RPM? No way!

Orr89RocZ

iTrader: (20)

You as usual blew my comments out of context

More cubes will make more power in the end because of airflow. As long as you have heads to feed it, more volume will move more mass flow. Period. Cant change physics

And by hp wins races its a generic blanket statement in racing. Ofcourse gearing and weight are factors. Power to weight is what i am refering to.

Geared correctly for each means the combo is optimized for the powerband.
10,000 rpm will need more gear than a 5000 rpm motor. I think you missed the point of that. Same reason shorter tires dont need gear and taller diameter tires need more gear. So say the 10k rpm car needs 6.13 gears. The 5000 rpm car needs 3.42's lets say. You honestly think there will be much difference in et and mph if both make 500 hp? In the same chassis that weighs 3500 lbs?

Dakota W.

GenX'Motorsport

This setup (TFS heads, Cam) on an LB9 with a hogged out TPI and 15pd's of boost would make about 500 RWHP using rough math. That would make for a pretty quick Thirdgen IMO.

Hhhmmm, Maybe I should get me some 175's?

Orr89RocZ

iTrader: (20)

And why are we talking about a 6 sec 2jz??

Andy jenson went 5.94 at 237 in a heavier car with a single turbo sbc

me420

Was it a LB9 motor? Whered it go?

RS Chris

Of course that papeweight of a car runs nines with only 400 hp. IT WEIGHS NOTHING. Put an SBC in an equivalent chassis with the same power and it should run the same times in theory. It's called power-to-weight ratio. That is the whole reason Honda's and imports in general car run as fast as they do with less power and cubes.

As for needing RPMs to make power, what do you have to say about diesel motors that never turn more than 4,000 RPM? Those are 5,000 plus pound vehicles running deep into the nines.

subroc

iTrader: (2)

Yup it was a LB9 motor. I ended up keeping the high flow TPI intake and sold the long block. I then sold the 700 as well.

Street Lethal

iTrader: (16)

This thread is a joke, all speculation...

Theory ehh? Sorry, theory means nada in the real world. Prove it my friend. Don't give me theory, prove it! If it is that easy to match that Honda, in theory, prove it! Car magazine after car magazine shoved big block torque (low RPM) in light weight vehicles with similar horsepower in comparison to that Honda, one even found its' way into a Chevy Chevette, and yet only mustered elevens. Go prove it then, prove me wrong...

Are you seriously this dense lol? Are you referring to supercharged and turbo charged diesels running deep into the nines lol? Let's see a low revving naturally aspirated diesel run deep into the nines like the naturally aspirated Honda above. Got any vids to share?

The point, my dear Chris, is that RPM, gear and tire size gives us our trap speed. Horsepower is our rate of acceleration, meaning how fast it takes us to get there, it is a MEASURE/RATE of acceleration, and weight only adds to that rate. RPM tells us how fast the prop is spinning, thus how fast our wheels are turning. Third, fourth, fifth, or "whatever" final gear in conjunction with how much RPM we are turning at the end of the 1/4 mile gives us our MPH, which is why high revving engines trap so high...

Incidently it is interesting to see how the LSX guys in the Drag Racing section are now turning their LSX engines above 7000-RPM now too to achieve their results. Hmm, perhaps someone should tell them to tone it down a bit, they might run a second or two faster by spinning it to 5000-RPM with larger gears out back...

jjcuff1

Only 3 ways to make power. RPM Cubes Compression. So bumping RPM will result in more power and faster times

Dakota W.

It's not theory, it's a science. A car with 2lbs per 1hp, with proper gearing, is going to get a faster time than a car with 4lbs per 1hp. Big Block torque is the reason why a v8 chevette ran such a slow time, no traction.