I have a 5.7 L98 in my GTA and i have decided to strip the TPI off in favour for a carb setup.
this is not a carb /Tpi debate topic....
i would just prefer to spend the money on the engine itself rather that upgrading to a better tpi setup.
As a Tpi upgrade is just as expensive as an engine rebuild and we have a problem getting mechanics to work on (American)tbi or tpi systems in the U.k..No body seems to know anything about them.
i am looking to gain more than 400 hp and more than 400lbs of torque.
Would anyone recomend having the stock L98 cast iron heads ported and polished or buy some aftermarket race heads?
Also what can should i replace the roller cam with or is the stock cam ok?
i have a Holley 650 spread bore double pumper ready to fit and a performer Rpm manifold.
I also have a dual point vac advance distributor and a mechanical fuel pump to replace the stock electric fuel pump.
I do not need to woory about emissions as i live in the U.k so that is less to worry about...
Is there anything else that i could do to increase the engine output while i have the engine partly stipped??
Any other suggestions would be apprieciated.

 

The stock heads will work up to near 400 HP with porting. That's pretty close to their limit.

The stock cam sucks. It's bad enough when it's still under a TPI. Get something like one of the "Extreme" series from Comp Cams, or a similar product (roller cam, very steep ramps, etc.) from some other mfr such as Lunati or Crane. You'll need new valve springs to go with whatever cam you get, as the stock ones are pure crap. Get the one that's about 225° of duration on the intake side at .050", and about 10° more than that on the exhaust side. That's about a good match for those heads and that intake (good choice of intake).

The carb is a little too small for that power level. You may get to 360 or 375 HP, but that's about it. HP = flow. If the carb is list # 6210, you'll have the best chance.

I wouldn't want a dual point distributor if it was my car, but it should at least get the job done. Those things are too much like work for my tastes.

As far as other things, exhaust.... rear gears..... torque converter.... suspension work, so that it hooks up to the pavement.... there's more to making a car fast than just getting more power out of the engine.

 

The 650 Holley is a list 6711 progressive double pumper 30cc primary/50cc secondary.which i bought because i have a Autobox.
i was advised to get this type of double pumper rather than the the double pumpers that pump at the same time to avoid cylinder wall washing and flooding.
Is this a good choice of carb or was i wrongly advised?
It was either that or a 750 vac secondary?
Any one else any other ideas?
I was also advised to get rid of the 3.23 posi rear end and get a 4.11 posi ?