hey, 305 and 350 TPI's. what do they share? are the intake manifolds (top and bottom) and injectors the same? and will the manifolds fit most aftermarket heads? good friend just got a '91 Z28 5spd with a 350 swap. clean clean car. i'll get pictures up later, but in the meantime, just wondering about some future projects. they're not exactly powerhouses from the factory. engine's already got a forged bottom end, but from there up it's stock. and please, dont ask me why he did that. your guess is as good as mine.
thanks man (or girl, if a female decides to respond... apperantly i have a problem with that)


Andy

it's not how fast you go, it's how you get there that counts.
ZZP XP cam, 1.6 rockers, 105# springs, speedbuilt FWI, 3.3" modular pulley, TOG headers,
3" exhaust, flomatched injectors
'97 GTP 14.06@100.6mph pre cam w/ 3.5" pulley, I/E

the tpi's in the f-body have a different egr system then the vettes

the intake base , the 4 center bolts are on the odd angle that most 87 up motors used

from what i rememebr the tpi base , runners and plenium , are all the same , the tb im not sure

and the 350 had larger injectors than the 305

A lot of people do lt1 intake swaps on the tpi motors because they flow better.

The intakes are the same, except the difference between centerbolt (87+) heads, and perimeter bolt (pre-87) heads (I believe the Y body actual started the center bolt heads in 86, but I can't remember). The injectors are bigger on the 350's, although I know plenty of people who put in an adjustable FPR and use the 305 injectors on a 350 by increasing pressure. This will work as long as you're not doing any major modding.

The other difference you will see between F and Y body, and some different years (I'm a little rusty on this info) is the presence of a 9th injector for cold start. this is obvious when looking at a motor because there will be a 9th smaller runner on one side of the motor, with a small injector at the base.

Also, the Y-body engines have no MAP sensor mounting hole or vacuum point on the plenum, due to the fact that they use the MAF sensor.

As far as head choice, most aftermarket manufacturers offer center bolt heads and perimeter bolt heads. When you are buying, just get the ones that match what you have and it will fit. I've seen people modify the 87+ lower intake manifold to fit pre-87 heads, but at this point TPI parts are so easy to come by it's just simpler to get the right manifold. The difference is the angle of the bolts. The newer heads have bolts that are in a more vertical position to the engine, rather than the 90 degree angle to the gasket surface

Hope this info helps. Email me if you have more questions. I've built more TPI motors than anything. I'm sure I've forgotten some of the info, as it's been a few years, but I can definitely help.

hey.

sadly, i do not know a vast amount of TPI info.

thirdgen.org has allllll the answers.


-Borsty

Borsty wrote:hey.

sadly, i do not know a vast amount of TPI info.

thirdgen.org has allllll the answers.

eh, it's ok. i've got enough info for now. i've tried to get him to go to thirdgen.org... but he's not very computer savvy and gets emberassed when he posts stupid questions and such. i'll head over there to do some browsing. thanks guys for the info so far. it should have the perimiter bolt heads. the TPI system came from the old 305 that was in the car, and since it's a '91, should be the newer bolt patterns. will the ports match up on the TPI engines and other heads?


Andy

it's not how fast you go, it's how you get there that counts.
ZZP XP cam, 1.6 rockers, 105# springs, speedbuilt FWI, 3.3" modular pulley, TOG headers,
3" exhaust, flomatched injectors
'97 GTP 14.06@100.6mph pre cam w/ 3.5" pulley, I/E

Quote:

Also, the Y-body engines have no MAP sensor mounting hole or vacuum point on the plenum, due to the fact that they use the MAF sensor.

not all vettes were map. I forget the year of the changeover but my friends 87' has a MAF.

tidbit for modding. the biggest bottleneck on that system is the lower mani. if you are gonna get seriouse swap out the lower mani first. this sounds a little crazy but you'll thank me



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when you beat someone in a civic people wine and make excuses
when you beat someone in a cavalier they pull over and check under thier hoods

HERE is a good read for you with all the info that you need

Like everyone stated. Its pretty much the same exterrior wise. Specially on the TPI system. The TPI is exactly the same except injector size. The computer is even the same. The chip inside the computer is how ever different to control the larger injectors. No matter the engine if its a SBC you'll have no problem what so ever finding headers/heads or any other parts for that matter.

NUTCASE . wrote:

Quote:

Also, the Y-body engines have no MAP sensor mounting hole or vacuum point on the plenum, due to the fact that they use the MAF sensor.

not all vettes were map. I forget the year of the changeover but my friends 87' has a MAF.

read that again...that's what I said.

Also worthy of note, a high-HP engine with a hefty cam will usually run better on a MAF system, becuase of the vacuum issues at lower RPMs with radical cams. However, you'll want an aftermarket MAF sensor to handle the high RPM flow (factory units tend to lose effectiveness much over 5500 RPMs)

NUTCASE . wrote:tidbit for modding. the biggest bottleneck on that system is the lower mani. if you are gonna get seriouse swap out the lower mani first. this sounds a little crazy but you'll thank me

VERY good advice. If you're building an engine, anything you can do up front like this will make your life easier down the road. I'd put an aftermarket lower intake and a good cam to start with. You can always fool around with other bolt-ons afterward, but I always like to avoid opening up an engine multiple times.

I still love TPI engines. The last one that I build was a stroked 91 Vette engine with the factory roller cam. I put a fairly radical cam in it (still roller), stroked it to 383 with a forged Lunati cam, 58cc Trick Flow heads, 1.6 Roller Rockers, Edlebrock lower intake and runners (I probably could have gotten a little more top end out of the Accell setup, but I opted for the Edelbrock for the facory look), Flat-Top Forged pistons, 6" connecting rods (yep, even with the stroker crank), and ran it with a modded Vortec ECU (for the sequential FI).

That was damn fun to drive.

Quote:

read that again...that's what I said.

ummm....oooops. thought you said MAP



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when you beat someone in a civic people wine and make excuses
when you beat someone in a cavalier they pull over and check under thier hoods