I have a GMP zz383 with the holley commander 950 engine mangement system and ha Stealth Ram intake. also the largest headers possible..

What kind of power can i get out of this ?
Is it possible to exeed the 425/449 numbers ?
Or is that the limit ? Emissions are not a subject here in norway on such old cars (1986 z28).

 

I think it's possible. The engine was rated with a 4bbl carb and dual plane intake. The SteathRam and tunability of EFI in general could possibly get you a bit more power than the factory rating, if it's tuned sharp.

 

would changing the cam produce more power? nice combo but i would need more from a 383...

 

I'd put it around 360-370 actual wheel HP. Heads, cam and compression of that engine will hold you back.

 

anyone else have this combo with hp #'s ??? i wanna see pics too...

 

I got 340 HP to the wheel on my zz383 with dual plane manifold, hooker lt headers, and Holley Street Avenger 770cfm. I could probably squeeze another 10hp with better tuning of the carb and timing...

 

I doubt you'll get any more than that out of it.

The HSR only flows about 425 HP, if the motor is in pump-gas trim (mostly determined by the compression ratio... which DEFINITELY applies to the ZZ383). Can't make any more power than the amount of air that passes through it will allow.

 

ONLY FLOW 425 Hp ? 1000CFM is supposed to manage to feed more than 425 hp....!!!

 

I think it will do more than that. HSR shouldnt hinder the performance over a dual plane carb intake. HSR has room to port if you are in doubt... with mild porting i was able to make 400whp on my 383 with a decent cam/heads combo. Thats through the TPI air box too, although gutted. My buddy's overbored stock crank/rods 360" motor made 330whp at 5600 rpm and then power went haywire due to bad valve float with 280xfi cam. Would easily have been a 350whp car with good springs and that was with old 190 AFR heads that dont flow like the newer 195-ish cc heads out there today, and he was at low compression, 9.5 to 1 on aluminum heads