[red82gt]

Hmm, it is making the same power (or less)than a 302 would make with the same parts. I would evaluate the overall health of the motor before changing the heads, the C6 will suck up some power but not that much. Shorty headers on a 408 is probably a mistake but you are still way down on power. I would check all the ignition components, the timing chain, re-install the cam making sure that it is timed correctly, etc.. before spending a dime on new heads.