How much H/P ZO6 have vs stock gto head

**jinouk67** · 08-26-2007, 08:09 PM

Hey guys, I have acquired a 2003 zo6 cylinder head. Redone 1500 miles ago by a shop in ca. per person i bought it off from. Has 3 angle valve job,manley dual coil springs capable lift up to .650,titanium retainers. How much more horse power would this head give compare to my stock 04 gto heads?
Is it worth to get it ported ? Anyone know a good machine shop ? Any ideal how much it would cost to get the heads ported ?

Any input will be appreciated.

P/s with my current mods, I goat has 362 hp @ rear wheel. I like to get up to 390 hp or close to 400 h/p if all possible.

**chris190** · 08-27-2007, 12:43 PM

What mods do you currently have on urs now?

**jinouk67** · 08-28-2007, 10:40 AM

Current Mods Are : Comp Cam Duration : @ .050 Lift Intake 222 Exhaust 224, 112 Degree Lobe Separation Angle, Lift Intake .566 Exhaust .
Comp Cams 7.4" Moly Pushrods
2800 Stall Torque Converter
Dyno Tune
Drag Bags
Slp Rear Stablizer Bar
Stainless Work Off Road Headers

**Rob** · 08-28-2007, 01:05 PM

Probably another 25-30rwhp after a tune.

**jinouk67** · 08-29-2007, 02:58 PM

Alright, thats not bad. With addt'l 25 rwhp i would be at 387 wrhp & i can add ported throttle body & maybe underdrive pulley to the mods.

**310stanger** · 09-07-2007, 05:13 PM

keep them the ls6 heads the way they are and you're good for the 25 to 30 more rwhp, ported? more then that. a nice set of ported ls6 heads ie patriot could be one hell of a nice lil upgrade.

**jinouk67** · 09-08-2007, 05:06 PM

I need clarification, U r saying the 243 heads i have will give me addt'l 25-30 rwhp w/o porting the head? If i want to get the head ported it maybe be better to get a whole new heads already ported such as patriot ?Can u or anyone tell me the zo6 heads i have with the work it has been done to listed on post above will work with my current mods ? I am thinking of installing this over the winter myself & i have to be honest, I don't know too much about car engines,the heads specs,cam specs etc... this is a another language for me and i just started learning.

**Rob** · 09-10-2007, 02:13 AM

The stock 243 won't gain that much at the wheels.

Go to ls1howto.com and do a lot of reading. Has tons of installs and really helps you get an idea of what needs to be done while installing parts. Very good site.