Okay you guys, lay it on me. I finally pulled my 305 TBI to go thru and freshen up while adding all the performance I can along the way.It will come back from the machine shop bored 0.030 over with new pistons, reconditioned rods with ARP bolts, all new bearings, plugs, etc. The crank polished, align hone checked, basically an all new platform to build upon. My question is,where do I go as far as heads and cam selection? I'm not looking to dragstrip it or anything, just squeeze out every last drop streetable power. I have two sets of 187 heads for this car (89' camaro) one with a fresh reconditioning, valve job, etc. The knowledge I'm lacking is compression ratio, where my power range should be and all that. School me fellas!

 

if you're having a motor rebuilt like you're talking go find a 350 and put the money towards rebuilding that block instead. it might come out cheaper since rebuild kits are cheaper as well.

 

Dont take the 305 to the machine shop. Instead, go to a JY and get a 350. Send it to the shop instead. Expect to pay around 50-100 dollars for the engine. Its the best 50-100 bucks you will spend.

 

Skid305,
Why not actually get an ALL NEW PLATFORM TO BUILD ON? From the sounds of that machine work you are planning to do what my son and I did to his engine. We got an incredible deal from the machine shop but still ended up with about $1100 in expenses. You could end up paying MORE for the machine work than you would pay to get a NEW 350 from one of the big name outfits.

I have seen NEW 350 long-blocks advertised for $1300 (Add $200 for shipping).

You might go and double-check the big-name outfits......

Just my

Kurt

 

I agree. You can get a new LO5 shortblock for $1200 from www.sdpc2000.com.

As far as TBI mods check out the TBI forum and the stickies that are at the top of the page. You have a lot of reading to do

TGO welcomes you!

 

Don't get me wrong, I understand the whole 350 thing. It's not that hard to figure out. Money aside, I think I'm gonna have fun with this one and not have another "me too" under the hood. I'm pushing on, and any info regarding head and cam selection would still be appreciated, Thanks

 

what are your goals for this motor? Mild 300hp or 450hp race only need a little info and then i'd be happy to tell you my reccomendations.

Although i agreee with that much works it's dumb not to get a 350 (no offense).

Laying that aside though i beleive a 305 is a good performer depending on the power output your looking at.

 

Here is the lowdown on this project. I bought this car new and have put every mile on it myself.(148,000) I have never so much as taken off a valve cover in what, 15 years, just changed all the fluids regularly and the usual upkeep. I have gone thru the entire car from the tires up and now I am at the engine. This car rolled off the line with 170 HP@4400 and my goal is to add 100 hp to it. A very attainable goal in my opinion. It has been a very dependable motor and deserves all the love I can give it. Besides that I want it to have all its original components, just running at their peak, when I hand it over to my son for him to drive. So that's where I'm at. Not building a racer, really , more like a restoration with some mild hop ups. It seems I'm under constant fire with the whole 350 thing but that's just not what this particular project is about. Again, any help is appreciated.

 

Well if i were you then i'd go with a new cam, full exhaust, full port job including a gasket match and a lot of bowl cleanup (or better yet vortec l31 heads Can be had for about 400-600$ for the pair but, will require some machine work to fit a mild cam)

More specific,

I'd look in to thecomp cam xe256 grind cam (comp reccomended this cam for my 305 build), a better manifold (if going carb'd i'd get a weiand stealth, performer rpm or any of the other good aftermarket 1s). If tbi your choices are pretty limited unless you have an aftermarket hood from what i've heard but, a performer manifold shouldn't have to much of a problem at about 300hp. For headers i'd go with 1 5/8 primary tubes in to a 3in outlet to a full 3in catback. This build should be pretty compatible with stock internals and still net you good vaccum and nice streetable power at a low rpm where it's wanted.

If you wanna go a little crazy like towards 350hp mark i'd get vortec heads, comp xe262 cam (still should be very streetable but, a little more mid to highend oriented) Go with the 335 powerhouse stroker kit (pretty much same thing as a 383 stroker idea except for a 305). Get hypereutectic pistons, forged I beam rods with a floating piston pin, all arp studs and rev her out 6k+.

My opinion is you should build it to a high hp street build if you got the money (get 350+hp so you can be the first on the board that i know of who has with a 305) show people that a 305 is a good performer).

 

That's what I'm talking about. I'm not scared of 350 horses. The exhaust is all done with Edelbrock TES 1 5/8" headers to a high flow cat to a 3" cat back. The bottom end should be done this week and the .030 over pistons are hypereutectic and have the ARP bolts on the rods. My concern is what the boring is gonna do to the compression ratio and is it better to run a milder cam or what? I do know that the heads and the valvetrain should be matched for the RPM range I'm going for, but I'm not sure of all my options. Iwas planning on going with the whole Edelbrock TBI performer package that has the manifold, cam, lifters, and maybe the heads, Im not sure about them though, maybe I'll look into some comp cams' info. What do you think about heads for the 305?

 

Take some time to read the swirl port head debates on the TBO board. Read through the threads at the top of the page and you will have a good idea of what you can do to the LO3.

 

Right on, Right on. I'll keep you guys posted.

 

I wouldn't go with the performer package myself it's kinda outdated and not your best bang for the buck imo.

If you want a cam good for pulling to 6k i'd use comp cams xe262 grind (talk to comp though and give them your build because, they knnow more about it than i ever will).

If you realy wanted 350hp out of it which would be sweet then i'd add vortec heads and a vortec intake, possibly mildly ported if you have the skill or the money for it. Don't forget 1.94/1.6 valving is about as big as you can go on a 305 and don't forget your building a 305, in this hp range your bore will start to hinder some flow i would expect. I'd look in to that powerhouse stroker kit, there is 1 user on this forum thath has it on his tpi setup with no tune and a mild cam and is pushing 300hp. He has the ghost flamed kick *** red z28 (hopefully someone can think of his name). The stroker kit is about 800$.

I have there pdf file because, i looked in to it back in the day, so if you'd like i could send you the catalog of it.

Your stock heads at this power level aren't going to cut it or come close to cutting it...

 

I would not recomend any 305 stroker. That money is best spent into another motor (350). Since you are not going the 350 route than you should just work with the 305 without touching the bottom end. The key to making any power with TBI is fuel and chip tuning. Without those you will go nowhere nomatter what mods you add. Dewey316 made almost 300hp with his stock headed LO3. He had headers, cam, intake and tons of chip work. There is lots of evidence that shows he may have been able to go bigger on the cam. Refer to the TBI board for more info.

 

Being at the point you are at right now, adding cubic inches is the easiest and cheapest way to get more power. For only $100 or so, your engine will make 10-25% more power just from the extra inches alone.

That is BY FAR the best way to get the most for your money is to ADD CUBIC INCHES!! its the cheapest and most effective way to get more driveable power out of any SBC. Make it bigger.

Aside from that, the next most important is the heads. Get a good set of heads and you'll be much better off. The 187 castings are garbage, throw them out. Look for a set of TPI cylinder heads (081, 083, 113 aluminum) and you'll be lightyears ahead of what your 187 castings could do for you. Also, if you check out the aftermarket, there are many options there too, even for a 305. I know TrickFlow makes a nice aluminum head with 58cc chambers, 1.94/1.60 valves and 175cc ports. Those would be VERY nice heads to have on a 305.

 

I beg to differ .


Swirl port heads are not as bad as everyone claims. In stock form TPI heads are only slightly better on the intake side and worse on the exhaust side. Which lessor do you prefer? Both heads can be ported to support pretty decent power. People have shunned these heads because they didn't understand them and it was easy to resort to hearsay. Dewey made almost 300hp on [b[UNTOUCHED[/url] 187 heads. That doesn't sound worthless to me. If you have crazy power goals neither TBI or TPI heads are the answer.

Flow Data

We like these heads now?

Swirl port heads

Garage ported 193's


Be sure to read the threads/posts by kdrolt, Fast355, and Dewey316. They are the ones that have the hard data and track times without any of the hand waving.

 

It seems I'm under constant fire with the whole 350 thing but that's just not what this particular project is about. Again, any help is appreciated.





I already stated that the 305 wouldn't be his best alternative but, he said this is what he wants people so why not try to give him a hand in what's best to build the most with the least.

We all know best bang for buck and an easy 300hp is vortec heads and a cam but, you'll never see this power up top unless you can rev it and have it hold together without strengthening the bottomend. Therefore if he wants substantial power he must at least add some arp studs in to the mix and think about better rods.

 

Studs for 300hp? Not really. Stock rods are fine. ARP bolts throught.

 

click on the link in my sig in order to see how to drain every last drop of streetable hp out of a 305.

 

I like to overbuild but, that's just me...

 

Man, you guys are all right. I've definitely got some homework to do. It seems my biggest challenge will be deciding where to draw the line. That and how long I want to stay married! I have been eyeballing some of those aftermarket heads tho, I'll try to keep you posted. Thanks again for the info, this site is a valuable tool.

 

His name is Tunedport 335, just for your info, I may try building a 377 for a 90 formula, since I got a 400 sbc block laying around somewhere.
Andrew

 

Skid, you are right about where to draw line and stay married. I started a HVAC company to support my hobbies. First to rebuild a Goldwing now a 87 firebird. I also have the "anemic" 305. I have no idea what has been done to it. It does have a flowmaster on it, thats all I know. The cat had been removed but is back on. I dont know how much power these things are supposed to have, but I can light up the tires from a stop and chirp second. If the only thing that has been done is a flowmaster, look at the exhaust. Also, these guys talk about there 350 and doing a rebuild at 80 - 90000, my car has 170,000 on it. Like I said I just got it this summer and still finding things out. Just found out about flowmasters last weekend, it did sound awfully good Also just rebuilt the rochester! Come to think about it, it might be a 350 in there.

 

Okay, knowing everybody's feelings on this build, I went and did it anyway. ( It's my nature ). The short block came back today bored 0.30 over hyper pistons, ARP bolts, etc. What I was thinking, along with the knowledge you guys can provide, is checking out that desktop dyno program that's out there. I may be opening up a can here, I don't know, but I think it's a viable option. I know it's kind of a drag to research a topic so much, but I hate when my ignorance amplifies my own stupidity! Just chucking that out there.

 

DDD is highly dependant upon the information put into it, makes some unrealistic assumptions, and tends to be overly optimistic.

Other than that, it's a fun toy.

Although the 305 can be made to put out a lot more power than the factory ever produced, but it will always fall short of the same-cost 350 (once all the necessary support upgrades are made, which are identical for either engine). It's water under the bridge for you now, but for the record, with the only differences being the cam, my 305 shortblock-based build wouldn't run at sea level what my 350 shortblock-based build runs at 5800 ft elevation. The differences between the cams is the 350 has less duration and more lift than the 305 cam had (plus is roller vs. flat tappet). An 8.6% increase in displacement produced more than 10% more power. Fuel economy is identical to slightly better with the 350. The 350 doesn't have to work nearly as hard in daily/highway driving as the 305 did. Etc., etc., etc.

 

Overbuilding is cool, but damn. I think i would stick with the standard bolts and whatnot. Of course, i probably wouldnt stick with the 305 either.

 

That's great imo glad you're doing 1 up. I agree you won't see near the power as 350 but, who cares it's plenty big of a motor to be a very solid performer, pm me your email adress and i'll send you my dd2000 program.

I've found it very very close to what most engines dyno at once you get use to what to enter and where.

the 3 things that are bad about the program imo is, headflow makes very small difference and in the real world is 1 of the biggest determining factors of the power you produce. The other is it only gives you manifold options like dual, single plane, or tunnel ram which makes them quite inaccurate for the specific manifold you go with. Lastly the header options are also very general but, hey the program itself was free and if nothing else seems to provide you with a general torque curve and something to play around with.

Btw my build may be moving along very soon, i've decided i'm going to buy the 335 stroker kit for it and the xe262h10 comp cam and a arp bolt kit insteada studs . My dad is said since i'm getting great grades and such lately he'd buy me the stroker kit or cam kit one or the other. So i'll have something to put together on mine soon for sure .

I wanna be the first on the boards to hit 350hp or so, would be kool as hell...

 

I have already made that with a 305 TBI, 301 RWHP with headers and the cutouts open((forced locked the TCC for the Pull only). I make 275 RWHP through cast iron manifolds and a single 3" cat.

 

not only that, but i've already ran a 13.03@103mph with a daily driven n/a 305!

while we support your goals, you will not be the first to reach 350hp from a 305.

 

I think he meant with TBI.

 

yah my bad what shift said .

 

After my 305 blew up i just swapped in the budget 350 longblock gm offer's and it has me in the 13's. Was only 2K.

 

Mine IS TBI! I cheated though and have a NON-GM ECM code running it. Can we say Rbob.

 

I know that was my point . Going 13's with a carb 305 isn't as hard and has been done numerous times. 350hp with a TBI equiped 305 is an amazing accomplishment on your behalf.

 

I wasn't claiming to be the first with a 350 HP 305. Just that I had one.

 

Hey, just a quick question, sorry if I'm being a PTA, what will bolting on a set of freshly redone 187's do to my compression ratio? Being bored out 0.30 I'm not sure. I thought the LO3 heads had 58cc combustion chambers, am I right? I'm an idiot, sorry.

 

SCCA American Sedan cars are running 375 Hp + form 305's relibily with a 650 CFM carb and and an Edelbrock Prformer RPM manifold and stock heads and valbe sizes. These are all mandated by the rules.

We have 305 cars beating 350 cars very regulary.

Steve
1988 IROC 1LE

 

They have an advertised 58cc chamber. Overboring your 305 and keeping the same chamber size will result in a slight bump in static compression.

 

can aluminum heads with the smaller 1.94 valves be bolted on the 305?

 

You can port aluminum L98 heads that have 1.94 & 1.50 valves with 58 cc chambers. They will work excellent on a 305, if you port them and use a 350 head gasket.

 

thanks guys...don't know what i'd do without this forum!

 

Just watch out the fact that nearly EVERYONE will tell you to get a 350. My 305 does what I want and makes me happy. If I wanted more, I would go get me a 454.



If you run the casting numbers it is just a lowly 305, with stock 187 heads, and a mild cam in it. Pulls 5,300 lbs to a 16.3 @ 86 mph, with a 10.3 @ 66 in the 1/8 and is getting 22 mpg on the highway.

Yes, I know the intake WAS leaking.

 

was the 187 head on the L-98? or was it the 305 head on the L-69 HO?

 

The 187 was the head found on LO3 motors. The L69 motors had the 416's which were an earlier version of the 081's (350 TPI heads post '87). L98 heads are 183's and are similar to the 081's except for a larger chamber and larger valves.

 

Hey Fast, any chance of seeing a full picture of that beast?

 

Not trying to thread-jack, but Yep, the engine info is a little dated and actually displays several configurations. Need to find the time to change that. Here you go.

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