First graph shows tpi with stock exhaust vs slp 1 3/4 headers and open cutout. 27rwhp and 21rwtq

Both of these are on stock tbi heads and cam



This one shows the differance between the cutout being opened and closed. Even with stock heads and tbi cam cutout gives more power.

 

Glad to see your cutout gained you some extra HP. Where's yours located?

 

It is welded to the end of the y-pipe then the cat and bolted to that.

 

Awesome, awesome, awesome! Very nice gains!

 

keep in mind that those results while very impressive would be far more impressive with a good flowing intake and matching cam filling those cylinders that allowed the exhaust to build even better flow inertia thru the cylinders, if that exact same data was taken from a 11:1 compression 383, with a stealthram and cam designed to maximize the exhaust flow like most nitrous cams the hp/tq spread would be much larger in favor of the headers
cams like Im currently running in my corvette (example)

http://dab7.cranecams.com/SpecCard/D...1=Display+Card
easily gain 40hp at the peak of the curve with good headers

 

91RS5Speed, If you don't mind my asking, what kind of gains did you get when you switched over to TPI? Do you have any dyno charts with TBI then TPI?

 

Just go to his site in his sig. He gained A LOT more with headers than he did with TPI, if anything.

 

Ah yes I didn't even see that site, thanks for pointing it out.

 

I gained 17rwhp & 70rwtq when I switched to TPI from TBI. w/stock manifolds.

 

70rwtq!!! Holy crap! :hail: :hail: