to all out there.....what kind of HP numbers have you been able to get using a GM TPI on worked 350's? what could one get using worked heads, ported intakes, higher lb. injectors, higher lift cams....etc...? 350HP possible?

 

Sure, 350 hp is possible Hell you can buy a crate motor from sdpc set up for tpi that's rated at 357.

 

see, you have to understand that the TPI system is not to strong for hp numbers. Its main point is low-end grunt (torque). Some guys on here have gone to about 400hp, or at least damn close, but by then, it is better to have a short-runner intake to take advantage of all that power.

Also, just an FYI, I've seen guys put down 350hp from TPIs, but also about 400+ft.lb.

 

thanks guys...for 350hp..does that require intake porting plus injectors,chip, etc.? has anyone done that on a L98 with aluminum 113 heads? i know the valves are small, but they could be opened up.

 

You would definetly need new aftermarket runners (and port them), a new aftermarket intake manifold (and port it), port the plenum, new injectors, and it would be a good idea to stroke the motor, and just getting some Vortec heads would be a good idea. If you needed to, you COULD do it with the stock heards, but new heads are worth the money. Also, one hell of a cam and some very nice piceces like rockers and valves would help a lot.

 

Well this is an age old story. if you have un limited funds, I believe that you could put a 350 hp nos system on it and it will live. Two extra pumps for fuel and some extra injectors and such. I have seen pump gas cars with 200 shots of nos and extra feul being injected living just fine. Also there is some car in last months HOT ROD mag that tells a little about them.

Just my thoughts and opions take it or leave it
later and
GB

rick

 

since you're asking about what other people have been able to get HP-wise out of a TPI motor, I assume you mean 350hp at the wheels, you can forget about it with a stock TPI N/A, worked or not.

 

yeah..i've heard that before...is the limiting factor the intake? could you port the intakes or use an after market one?

 

my car weighs 3750 with me in it. It runs 103 mph in the 1/4 mile = 315 RWHP (according to HP calculators) = 362 CHP (15% drivetrain loss)

This is accomplished with stock TB, Plenum and runners bolted onto a SDPC TPI base and stock Vortec heads. So yes it can be done!

 

The highest I have seen is around 400HP at the flywheel. This translates to around 320-325HP at the rear wheels. Kevin91Z has just got his car running again with a few more mods. It will be interesting to see what the dyno results will be. He has installed modified SLP runners among a few other things. Allen

 

A long long time ago...

When my only mods were heads (not ported) cam, bored over block, and a edelbrock baseplate (not ported) I had stock runners,plenum, tb, etc.

With flowtech headers.. I'd guess around 350 give or take. Car ran 13.50 @ 101mph, 3600lbs with me in it. SO you take a guess.

Now of course evrything is ported, along with siamese slp runners, and a blower, and i'm into the 5xx range I think.

-- Joe