This is the exact head that powers Rick Abare's 530 rwhp 3440-3470lb Trans-Am into the 9's at over 138 mph on pump fuel.
My first dyno run = ~100hp more than expected even the Dyno operator was confused by wheel spin...:).Much more to be found in this combo only two runs were made... rest I tuned on I-75!!
3000rpm = 3psi and 420lb/ft with 240hp
4000rpm = 4psi and 480lb/ft with 360hp
5000rpm = 5psi and 517lb/ft with 495hp
6200rpm - 6psi with 495lb/ft with 570hp
The ONLY mods to this 1996 TA are:
200cc LT1 Porting and Cam package
Forged 383 at about 8.9:1
83lb injectors with my own custom 2 bar tune and 2 bar MAP on stock ECM
Long Tube Pacesetter Headers
Magnaflow 3" Cat Back connected to a Pacesetter Y-Pipe (Im sure this is just killing power).
Single Walbro 255l/hr pump.
McLeod Street Twin with Alum Flywheel
Everything else (as in.. the entire car) is fully stock including the Traction Control and AC (it still works) and spare tire (and amps and subs).
So, this car is HEAVY, and ran 124mph in the 1/4 mile. The ZR1 might run 132mph and is about 900lbs lighter.. so YEP that just about confirms HP.