I just picked up an LG4 block with a spun rod bearing for $50 with only 50,000 miles on it. I am getting ready to send it in to a machine shop and have some questions I need answereing while I can't work on it. 1st this engine originally had a carb, is the TPI from a 91 305 gonna be a bolt-up deal? If it is why do I need the cold injector sensor? Is it because it was eliminated after 88? Will the stock TPI manifold be sufficient for up to 500hp? When I get the ECU and the wire harness for it, is it best to use the one from a 91 Camaro or will one from an 85 with TPI be ok? The 85 still used the cold start plug. Will center bolt valve cover be bolt-in also? I think that's it for now. Thanks so much for the help!

 

Depending on the year of the LG4 case, you may have a one-piece or two-piece rear main seal (and mating crankshaft).

Avoid the '85 ECMs, since they are the older, slower units for MAFs. '86 and later are better for MAF, and '90-later are better for S/D installations.

If you use a '88-later ECM, you will not need the cold start control nor injector.

A TPI induction system will be stretched to support even 400HP in stock form, let alone 500 HP.

The rocker covers are dependent on the heads, not the case. Your heads will have to match the type of TPI unit you select, so that they will bolt up without alterations (although the alterations are minor). Any heads up to the SBC-II family will bolt on your case, and even the LT1s will work with some machining and welding.

Decide which way you're going to feed the engine (TPI, LT1, carb, aftermarket injection, etc.) then pick the mating components.

 

Sorry, I have more questions.

What parts from a 350 fit onto a 305? Since the TPI unit won't support 500hp I have decided to go with a carb. So when I look for a cam, for example, should I find one that fits the block or the heads? Does anyone know it the Edelbrock power packages are any good? Would going with the GM performance parts Vortec heads and manifold be a better idea? Remember I'm going for 500hp if I can, otherwise I'll take 400. What are some good heads for under $1000? Oh and since I'm goona use the 85 LG4 with the 2 bolt mains what car should I get the ECM from? Think that's it for now, thanks so much for the help, I'm used to my Cavalier's 4 cylinder engine and I'm not used to the muscle engines, getting there quickly though.

Nick

 

i seriousely doubt you find a cam/head/induction system for 500 NA HP on a 305, but i've been wrong before. if you run a carb you wouldn't need an ecm. any SBC cam will fit any SBC block, only thing to watch for is factory roller cams in non roller blocks. think of the engine as a package working together and not a bunch of randome bolt on parts that may or may not be matched for best preformance. if i were you i'd do a little mroe reading and research before jumping into this 500 HP 305 project.

 

Ed is right.

And even 400HP is a real stretch for a 305 that will have enough manners to be able to drive on the street. If you want that kind of power level and some streetability, you really should consider more displacement. Stretching power beyond 1HP/CI starts to get into the realm of better engie controls, a sacrifice of low-end torque and smooth idle, and will demand a higher octane fuel and compression pressures that aren't going to be really compatible with daily driving.between stoplights.

 

Ok maybe 400 is too much HP, but I'll give it a shot. Should I get the ECM and wiring harness from the 85 Camaro or do they not use any sensors in that year? I wa also going through my Jegs and Summit catalogs and didn't notice anf pistons for the 305. I have a 3.530 bore, do they have them and just not list them? I wasnt to bump my compression up to 10 so I can use 91 octane gas, that should give me a little more power. Let me know if you have more info for me, thatks again!

Nick

 

if you have a 305 you don't have a 3.530 bore. jegs and everyone else has pistons for a 305 they aren't listed because they aren't that popualr, they only show the biggest selling parts. do some research you don't need senser of an ecm if you go with a carb, unless you want to use a q jet and the factory induction, but then you should lower your HP goals another 150.

 

According to my Haynes manual the 85 Camaro with 305 LO engine has a 3.5" bore and I have gotten it over bored .030. I'll call summit for pistons. I am running a carb, I'm going with the Edelbrock performer carb. Also I was talking to my father in law and he has an 84 Camaro with a 305 pushing 423HP and it's a daily driver, so it can be done, although expensive, but not impossible. Thanks again for all your help. One more thing though, how much HP can the stock crank handle?

Nick

 

Well then the Haynes manual just plain sucks. A 305 has a 3.735" bore. Unless you are wrong and are looking at the 267 cid engine that does have a 3.5" bore, or they are wrong.

I would suggest you do a lot more research before you do your buildup, or you will have a complete dog crap engine.

 

I am doing tons of research, and learning from you guys is a huge part of it, no better way to learn than from people who have already been there.

I have recently been thinking about switching to roller tip lifters, should I also covert my rockers and cam to roller, or do I have to keep the cam the way it is, hydraulic? I know I'm gonno go with a 1.6" lift and a 205-220 degree cam to maintain streetability. I'm gonna get a forged crank for sure. Any other suggestions?

Nick