There are so many false claims by companies out there, I was wondering what gains can really be expected by these mods. First off, I have an L98 Formula with a 3inch cat back, high flow cat and stage 1 chip. Purchased the car with the above mentioned mods already on it. I have some cash to throw into the car, but don't know very much about TPI (I've been driving 60's muscle my entire life).

Here are some common mods and I'd like to know what gains can honestly be expected by them.

Aftermarket runners, manifold and ported plenum. Per say like Edelbrock. What can be gained by these mods if all done at once or one at a time?

Adustable fuel pressure regulator. I have heard great things about this mod and it's fairly cheap as well. What can be seen by boosting the pressure a little?

Air Foil: Cheap and if it gains you a tenth or two it might be worth it.

Underdrive Pullies: How much HP does it free up?

Throttle body: Is anything really gained by this on a relatively stock 350? I think the stocker is fine. What gains have people seen?

Superram: Once again, what can be expected out of this set up on a fairly stock L98? Same for Mini Ram

Headers: How much is gained by a good set of shorties? How about Long tubes?


There are so many myths/falsehoods running around out there, I'd like to see what everyone has truly gained by these mods and feel it can be helpful to everyone on the board. I'm especially interested in what is really gained by just adding per say, better runners or a better manifold, but I really want to know about all these other mods as well.

 

Forget underdrive pullies..they're worthless.

Even a stock L98 is extreamly intake flow restricted. Any intake mods are an improvment. I recommend porting a SLP baseplate and runners, and port the snot out of the stock plenum. The throttle body, however, should probably be about the last thing. The airfoil is a good idea..but for $3 you can smooth out the gap in the center with some epoxy.

The Super ram is pretty much junk, but the miniram is a very good street setup if you don't mind the cost. Of course the cost really isn't much more than the above mentioned mods to the TPI.

The AFPR mod is a very good chep little mod..and especially useful after intake mods.

Headers, as on any car, are a very good start. Long tubes are better, but short tubes work fine and are much more readily available.

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Headers would be a big improvement. The stock y-pipe and manifolds are some of the worst restrictionson that motor. And you're not getting full potential of the cat-back without headers.

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I'd love long tubes, but heard there are all kinds of clearance problems both on the install and in terms of ground clearance.

What is a round about gain that would be seen from an aftermarket set of runners? Same for manifold. I'd love to get it all at once, but may not be able to cause I have some other things in the works.

WIll I see a 20hp gain from aftermarket runners and manifold along with a ported plenum?