getting TPI to 350HP
10-09-2004, 04:27 PM
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getting TPI to 350HP
Hello all,
I am interested in what anyone here would do, or has done, to get a stock 91 350 TPI into the 350+ horsepower range.
My 91 firebird formula 350 has 152k miles now, so should I consider a rebuild first. It shoots out a puff of smoke on startup (I figure it is worn valve seals) but otherwise runs great (does not leak or burn any oil that I can see or make any lifter noise).
Is the TPI system capable of supporting this kind of HP or would I be better off going another route.
What are the recommended heads, intake, cam, etc. if I keep the TPI?
Thanks,
Chris
I am interested in what anyone here would do, or has done, to get a stock 91 350 TPI into the 350+ horsepower range.
My 91 firebird formula 350 has 152k miles now, so should I consider a rebuild first. It shoots out a puff of smoke on startup (I figure it is worn valve seals) but otherwise runs great (does not leak or burn any oil that I can see or make any lifter noise).
Is the TPI system capable of supporting this kind of HP or would I be better off going another route.
What are the recommended heads, intake, cam, etc. if I keep the TPI?
Thanks,
Chris
10-09-2004, 05:03 PM
#2
Here locally there are cars in the 400 HP range at the flywheel with a highly modified TPI. Yes you will need to have your engine refreshed. Here is what is done.
1. A good flowing set of heads such as AFR's, Trickflows, Edelbrock Vortecs etc.
2. The cars here are running around 10.5:1 compression with of course aluminum heads. When shooting for 400HP you need every little bit. For 350 you can lower the compression to say 10:1.
3. You have a Trans Am so you will need to modify the air filter assembly. The stock setup will not support that type of horse power. Dyno Don's car was showing an intake restriction on his last time at the drag strip. He has your setup and he is in the process of modifying it. I also have a 89 Trans Am and I made my own Cold Air Induction. For 350 HP the SLP one should do you.
4. You will need a good set of headers of at least 1 5/8". You will need a good flowing exhaust with 2 1/2 inch from the headers to the cats. Get a good wye in place of the factory one. Then you will need 3" back to the muffler and get a good flowing muffler.
5. Modified TPI. Edelbrock or equal intake manifold port matched. I had mine extrude honed for the extra 25 CFM. Good set of runners. Either modified SLP or AS&M. Ported plenum. 52mm Throttle body.
6. Last the cam. The computer programs show that 400HP is possible with a ZZ4 cam. The cars here are running 212 degrees on the intake and up. Kevin is running the Hot Cam with 218 degrees duration on the intake side. 1.6 Roller Rockers. You don't need to go wild on the cam as long as everything else is up to par.
Hope this helps. Allen
1. A good flowing set of heads such as AFR's, Trickflows, Edelbrock Vortecs etc.
2. The cars here are running around 10.5:1 compression with of course aluminum heads. When shooting for 400HP you need every little bit. For 350 you can lower the compression to say 10:1.
3. You have a Trans Am so you will need to modify the air filter assembly. The stock setup will not support that type of horse power. Dyno Don's car was showing an intake restriction on his last time at the drag strip. He has your setup and he is in the process of modifying it. I also have a 89 Trans Am and I made my own Cold Air Induction. For 350 HP the SLP one should do you.
4. You will need a good set of headers of at least 1 5/8". You will need a good flowing exhaust with 2 1/2 inch from the headers to the cats. Get a good wye in place of the factory one. Then you will need 3" back to the muffler and get a good flowing muffler.
5. Modified TPI. Edelbrock or equal intake manifold port matched. I had mine extrude honed for the extra 25 CFM. Good set of runners. Either modified SLP or AS&M. Ported plenum. 52mm Throttle body.
6. Last the cam. The computer programs show that 400HP is possible with a ZZ4 cam. The cars here are running 212 degrees on the intake and up. Kevin is running the Hot Cam with 218 degrees duration on the intake side. 1.6 Roller Rockers. You don't need to go wild on the cam as long as everything else is up to par.
Hope this helps. Allen
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