305tpiz28

i just bought a 87 iroc with a 305 tpi and auto tranny and am looking to swap in a 350. Ive done quite a bit of reading on the subject but i am hoping someone can give me a solid answer to one question. What should i get the engine from to make this swap as easy as possible? From what i have read i need to get one from a 87-92 donor. Is this correct? I know i have to change the prom and either get an AFPR or bigger injectors. Is there anything else that may give me problems? All the wiring should be the same right? Thanks in advance.
Adam

Kontrax

all you need is the long block and computer, everything else should bolt right up. you will need an 87 or newer long block because of the angle on the manifold to the heads. try and find a smashed up parts car. i dont know about where you live, but in this state you can get a tbi motor for dirt cheap. no one wants the tbi so take it off, throw it away and put the tpi on

305tpiz28

would and older chevy block,say early 80's, still mount up to the orginal location of the motor mounts? and just need different heads and intake?

five7kid

iTrader: (14)

You can make an early '80's 350 bolt in with minor modification (intake base center bolt holes). You don't need to change the heads.

The flexplate will be different. Get one for '82-'85 3rd gen V8 auto application.

Spectre

check the papers or performance shops for a rebuilt
chevy long block ..

Kontrax

pre 86 heads are what you dont want if your going to use tpi, the centerbolt heads have a different angle then 86 and earlier. if you try to use 86 or ealier heads, the manifold will have a gap between it and the heads.

five7kid

iTrader: (14)

That is simply not true.

The only difference is the center two bolts' angle on each side.

Kontrax

it is true. thats how i knew jegs sent me the wrong manifold. brought it down to the machine shop and put it ontop of my motor which was an 89 with the centerbold heads, it had a big gap between the manifold and the heads.

five7kid

iTrader: (14)

There was something wrong with your engine, something wrong with the manifold, or both.

But, the geometry of '86-earlier and '87-later intakes was the same except for the angle of the center two bolt holes on each side.

Kontrax

well theres nothing wrong with the engine because its running great. i sent the manifold back and they said it was made for 86 and earlier and thats why it didnt fit. the machine shop dude said thats the difference between the 2, the angle. i know the centerbolt heads have the different angle on the bolts, but im tellin ya it had a gap between it and the heads. about as thick as an eraser on a pencil. he says the angle is like a 90 on the center bolts and pre 86 is like a 70 or 60. have to ever tried to put a pre 86 manifold on 87 later heads or are you just saying that because you read it somewhere? seriously.

five7kid

iTrader: (14)

If you want to "prove" who's right, start a thread on the topic on the Tech General Engine forum and see what others have to say. Go ahead and tell your story as your "evidence".

After 30 or so replies, I'll promise not to say "I told you so" before I lock the thread to avoid using up any more unncessary bandwidth.

I'm not going to argue with you about it any further on this thread.

Kontrax

im not arguing at all, telling you what i saw. could care less whos right thats childish. i just asked you a question and just didnt get an answer. no need to get huffy puffy.

Guest

Seriously? People do this every day. Its commonplace. The only difference between pre and post is the center 4 bolts on the intake, they are at a different angle relative to the intake face. The 'early' style is 90 to the head (as are the other 8 bolts) and the 'late' style they are at 72 degrees to the face (they are more vertical than the others). The intake face angle itself has never changed.

Sounds like you bought my old/new Edelcrock intake that I sent back to Summit Racing because it was milled wrong. They (Edelcrock) told me my engine wasnt machined right... Too bad for them it was original factory and the stock manifold fit fine.

As to the original question, get yourself an 87 or newer block and heads and keep the rest of the 305 stuff. You could swap injectors, knock sensor and chip, but its not totally necessary. Thats the easiest way. The hard way is use an earlier block (85 or older) and get a new flexplate, forget about having a roller cam (unless you want to shell out the bucks for aftermarket stuff) and some heads. 87 up heads are a direct fit, the 86 and older you'd need to modify the aforementioned center 4 bolt holes with a drill, reamer, mill, whatever... and then it'll fit just fine. Personally... I'd take the easy way Oh yea... avoid the 1986 bastard blocks at all costs. They are mix+match and just too much headache to explain, not to mention you dont get a roller cam either.

Kontrax

you know your right. they did send me the edlebrock manifold and after that disaster i switched to holly. the engine is already done and in the car running strong. the block i got was from an 88 or 89 1500 pickup, not sure because i didnt have the title to the truck.