my friend has a 1991 gta with a tpi350 and was wondering what type of cam and head package he should go with, keep in mind that the bottom end is stock aswell

 

We need more info than that. Is this a daily driver? Street/strip? Can you do your own custom chip tuning? Are you going to upgrade the intake manifold also? Headers? Does he want a 13 second car, 12 second, or 11 second? There are lots of heads and cams out there for small block chevy engines, but it requires the correct combination of parts to work with the tuned port engine.

 

it will be a street strip car... chip tuning is a go (planned on doing it anyways) , headers (yes), intake (maybe), the car runs 14 flat as it sets with minor mods 3.73s, underdrive pulleys, k-n filter directly off of tb, and a fp regulator

 

That's probably the biggest deciding factor here. When you say intake, do you mean the induction system, a ported plenum and aftermarket runners and base, or a completely different EFI system like a StealthRam or MiniRam?

 

hes going to port out his own intake at our school

 

I'm in the same boat as well. I will be doing minor porting of the stock intake and would like a low 12 sec car if possible with the TPI. If not, then I may throw on a modified LT1 intake. Good luck with the GTA! And thanks everyone for any info.

 

There's not a whole lot of gain in doing that. Porting the plenum is a worthwhile endeavor, but porting the stock runners and base often hurts more than it helps. Keep in mind that the stock intake just doesn't do much above 5000RPM, so match the cam and heads to that. A good option would be GMs Vortec cylinder heads matched with SDPCs lower intake manifold, with a cam in the mid 220 duration range.

 

I disagree. I was able to go 13.23 @ 107.50 with a stock ported intake, plenum and runners, with a ZZ4 camshaft, ZZ4 heads, and 1 3/4" headers. A stock ported intake manifold, if done correctly, is only slightly smaller than an aftermarket Edelbrock intake right out of the box. However, an Edelbrock intake can be ported much larger for even more flow.
Since you can do your own custom chips, I highly recommend the Trick Flow 23 degree heads, and the Comp XFI268HR-113 camshaft. Pair that with an Edelbrock intake manifold (the only aftermarket one left), AS&M semi-siamese runners, and either SLP or Hooker headers. You'll also want an upgraded transmission, and a 2400 or 2800 stall converter.

 

If you really wanna go fast and go faster in the future your BEST BET is to take the TPI setup off and sell it and use an LT1 intake or HSR.

When I was gathering info to do my heads/cam swap in my 87 years ago,I saved A LOT of money by selling my TPI on ebay (which damn near paid for my Vortec heads) and went carb'd. Not saying you should do that,but,fuel injection is EXPENSIVE. It was going to cost easily $1500-2000 more just to keep my FI...not worth it IMO.

 

will you really get that much of a difference with removing the TPI setup?

 

It really depends on the setup, but in most cases you lose a good bit of torque at low RPMs that aren't used in a racing environment. But what you lose in low RPM torque you REALLY make up for in higher RPM horsepower - gains above 4500RPM. If you want to feel fast, keep the TPI. If you want to go fast, get rid of it.

 

he is running 14 flat now, with stock heads, cam, intake ect. he has a k-n filter right off of the intake, pulleys, fp regulator, and 3.73s

 

I have heard of switching the tpi for the lt1 intake, but isn't there some type of modification that has to be done with the way the thermastat water outlet is? O and I'm the guy with the tpi that we talking about.

 

Everything you need to know about that swap can be found at www.lt1intake.com

 

I second the XFI268 cam.. its a good cam for TPI. Just about as big as i'd go in LTR TPI setup. you can step up to a 503 comp cam which is 224/230. not a bad grind for a hot street car. should go 12's easy with modified TPI and great tune.

If you do an intake swap, i'd recommend the HSR or holley stealth ram. I went to one on my stock L98 TPI car and so far picked up 2 tenths and 2.6 mph in the 1/4 mile. no other changes. And when i say 2 tenths, that is a solid .17 seconds difference from my best TPI time of 13.63 at 97mph in the winter air of 50-55 degrees, to my best hsr time of 13.46 at 99.6mph in August heat of high 70's low 80s