Do you have headers already? If not, they would sure sound sweet and help with power more that roller rockers. What is your initial and total timing set at? Have you run the car with a wideband A/F ration monitor on it?

1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)