On my m6 LT1, I have Mac Headers, 3:73 gears, Hi-flow cat, custom PCM programming, aluminun drive shaft. What else can I do to gain horsepower besides the obvious heads, cam etc. Any ideas? I am new to this so take it easy.

 

you could always do a throttle body bypass....easy 5-7 rwhp...

Throttle Body Bypass

 

Catback, 1.6 Roller Rockers, Cold Air Induction and perhaps an electric waterpump should be good for about 5-10hp each.

 

or you can get a cutout. its cheap and sounds great. I took the ghetto approach to this and just un hooked my exhuast after the cat so the exhaust doesnt go through the muffler

 

Forgot to mention that My hawk is a ram-air and has Borla catback

 

Mark are you Polish? You have polish last name?
Anyway you can reduce your car weight or relocate battery (those are rare options but you asked for those It will give you more traction...Change fluel pressure regulator....I have M6 also and for me the best mod are 4.10 gears and PRO 5.0 shifter
4.10+M6=FUN!!!!!

 

Also, I have a B&M ripper shifter, subframe connectors too LOL. i figure I am pushing about 360hp right now. I want 400HP. What else fellas?

 

Are you sure you are pushing 360HP? I think that this will be more like 320RWHP...

 

RWH, you are probably right, but crank hp is around that figure, and yes, I am Polish, check your email :-)