[s346k]

600 na? i would throw the dyno number in the trash and simply look for a setup that will get you what you want. if a dyno number is what you want, get the car to 580 and shop dynos, you'll eventually find one generous enough to fulfill your goals.

if you want a high output na setup you will need a ported msd/hi ram, at least a 95 mm tb, 2" primary header, ethanol and worked cylinder heads to get started.

edit: an LT2/ZR1 tb will give the best bang for the buck, but not the most gains. id look to pick up 15-20 whp from the intake manifold/tb.

edit2: i now see you have ported cyl heads and ethanol. do you have any real performance measures on the car? those dynojet numbers look pretty soft, but dynos be doing dyno stuff.