305 TPI to 350 Question
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Joined: Oct 2007
Posts: 105
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From: OS, CT
Car: 1987 IROC-Z
Engine: LB9
Transmission: 700R4
Axle/Gears: BW 2.77
305 TPI to 350 Question
Will the TPI setup from a 305 (intake, fuel rails, etc) fit directly on a 350? For instance, if I buy a 305TPI camaro, can I take the TPI and put it on a 350 for a 350TPI car? I just can't find one with a 350 already in it.
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Welcome to thirdgen.org.
A qualified "yes" to your question. What the 350 is, that's the important question. If it's from a 1973 truck, no, it won't fit directly, but can be made to fit.
Let's go through the basics:
1968 - 350 small block Chevy introduced into general production.
1968-1979 - not many changes. Some have 4-bolt mains, primarily 4-bbl and truck engines, but 2-bolt mains aren't "bad". Quality control issues plague the whole era, with porous castings, core shifts (thin cylinder walls, for instance), poorly controlled machining, etc. Heads put on them varied widely, the vast majority of them being very poor from a performance standpoint.
1980-1985 - The dipstick was moved from the driver's side to the passenger side. Oil pan changed accordingly. Some improvement in quality, mostly still poor heads.
1986 - Rear main seal design changed to one-piece, requiring a change to the block, crank, and flexplate/flywheel.
1987 - Roller lifters introduced into production. Trucks still got the cheaper flat tappet lifters/cams. Intake mount bolts to the heads were changed to 72 degree angle for the center two bolts on each side. Valve covers changed from perimeter mount bolts to center mount bolts.
1988 - "Swirl port" heads introduced with TBI EFI (trucks and full sized cars only).
1992 - "LT1" Gen II SBC introduced in Vettes (1993 in f-bodies). Cranks, rods, pistons, lifters basically the same as before, everything else different.
1996 - "Vortec" heads introduced on truck line. More like Gen I with a twist.
See why the "yes" is qualified?
Then, what you have to do to make the 350 work depends a lot on what car you get. . .
A qualified "yes" to your question. What the 350 is, that's the important question. If it's from a 1973 truck, no, it won't fit directly, but can be made to fit.
Let's go through the basics:
1968 - 350 small block Chevy introduced into general production.
1968-1979 - not many changes. Some have 4-bolt mains, primarily 4-bbl and truck engines, but 2-bolt mains aren't "bad". Quality control issues plague the whole era, with porous castings, core shifts (thin cylinder walls, for instance), poorly controlled machining, etc. Heads put on them varied widely, the vast majority of them being very poor from a performance standpoint.
1980-1985 - The dipstick was moved from the driver's side to the passenger side. Oil pan changed accordingly. Some improvement in quality, mostly still poor heads.
1986 - Rear main seal design changed to one-piece, requiring a change to the block, crank, and flexplate/flywheel.
1987 - Roller lifters introduced into production. Trucks still got the cheaper flat tappet lifters/cams. Intake mount bolts to the heads were changed to 72 degree angle for the center two bolts on each side. Valve covers changed from perimeter mount bolts to center mount bolts.
1988 - "Swirl port" heads introduced with TBI EFI (trucks and full sized cars only).
1992 - "LT1" Gen II SBC introduced in Vettes (1993 in f-bodies). Cranks, rods, pistons, lifters basically the same as before, everything else different.
1996 - "Vortec" heads introduced on truck line. More like Gen I with a twist.
See why the "yes" is qualified?
Then, what you have to do to make the 350 work depends a lot on what car you get. . .
Last edited by five7kid; Oct 15, 2007 at 06:12 PM.
Thread Starter
Member

Joined: Oct 2007
Posts: 105
Likes: 1
From: OS, CT
Car: 1987 IROC-Z
Engine: LB9
Transmission: 700R4
Axle/Gears: BW 2.77
Re: 305 TPI to 350 Question
Good point. My plans are to keep this simple if I have to go this route, because I learned, at the cost of my current Camaro, that I haven't the time for big projects. I want to get a 350 that is out of a car in the same range as the recipient Camaro. I'm looking for a 87-92 IROC, T-Tops required. It's such a pain, I've found several IROC's in this range in beautiful condition for a good deal, but they all have 305's! My plan is to just drive the 305 while I build a solid 350 to put the TPI on. I looked into aftermarket EFI systems but they're just too expensive, well over a grand for a complete system. I'm dead set on EFI because I need efficiency and driveability to go along with power, since I'm gonna be driving this car a lot. It's an addiction.
So whaddaya think? Do I make sense?
So whaddaya think? Do I make sense?
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Sure. You're right in step with the third generation frustration.
I won't try to give this any more credence than it's due, but I've heard 350's and T-tops didn't go together, at least for some years. Certainly if you want manual transmission, that never went behind a 350. Hey, couldn't hand those Vettes their heads, right? That just wouldn't be "CC" (corporately correct).
The only '87-'92 350's with "good" heads came in 3rd gens and Vettes. Keep that in mind.
Another possiblilty to consider: http://www.sdparts.com/product/SD360...ripEngine.aspx . Might seem pricey, but put aftermarket runners along with the rest of your 305 TPI, headers, and you've got yourself one beasty TPI.
I won't try to give this any more credence than it's due, but I've heard 350's and T-tops didn't go together, at least for some years. Certainly if you want manual transmission, that never went behind a 350. Hey, couldn't hand those Vettes their heads, right? That just wouldn't be "CC" (corporately correct).
The only '87-'92 350's with "good" heads came in 3rd gens and Vettes. Keep that in mind.
Another possiblilty to consider: http://www.sdparts.com/product/SD360...ripEngine.aspx . Might seem pricey, but put aftermarket runners along with the rest of your 305 TPI, headers, and you've got yourself one beasty TPI.
Thread Starter
Member

Joined: Oct 2007
Posts: 105
Likes: 1
From: OS, CT
Car: 1987 IROC-Z
Engine: LB9
Transmission: 700R4
Axle/Gears: BW 2.77
Re: 305 TPI to 350 Question
I want to disagree with you on that 350's didn't come with T-Tops part, but when I think about it maybe that's why I'm having so much trouble finding exactly what I want. It seems the cars that I like all have rebuilt engines...hmm...
Trans doesn't matter, I have no quarrel with the 700R4, and if I pick up another one I'd put the valve body on it that makes it shift manually anyway.
As for the engine, that would be a killer powerplant, but I kinda wanna build the engine from the block up, just for the experience. I have rebuilt an engine, but it wasn't mine. I'd rather get a block, have the shop clean it up and bore it if needed, and then put mostly new parts in it, probably including the heads.
That leads me to another question. Are the heads of 350's and 305's interchangeable too? Or rather, would heads for a 350 fit on a 305 directly?
Trans doesn't matter, I have no quarrel with the 700R4, and if I pick up another one I'd put the valve body on it that makes it shift manually anyway.
As for the engine, that would be a killer powerplant, but I kinda wanna build the engine from the block up, just for the experience. I have rebuilt an engine, but it wasn't mine. I'd rather get a block, have the shop clean it up and bore it if needed, and then put mostly new parts in it, probably including the heads.
That leads me to another question. Are the heads of 350's and 305's interchangeable too? Or rather, would heads for a 350 fit on a 305 directly?
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