Not much power

[HighwayThunder]

My 66 T-bird doesn't seem to have a lot of power. Acceleration is sluggish.

The engine is a 390, over-bored .030", balanced crankshaft, Edelbrock aluminum heads and intake manifold, Street Demon 650 carb, Capacitive Discharge Ignition, Competition Cams hydraulic roller lifter system, C6 transmission with torque converter to match the CompCam's power range, 3.7:1 rear end.

You'd think that the engine mods would make my T-bird a muscle car... but no.

Could it be that the curb weight of the car at 4200 lb. is just too much? Is there a factor that I'm ignorant of?

[simplyconnected]

Richard, you have tried different cams and have gone with EFI and a "RV" roller cam. HP isn't simply a product of volume and gear ratios. It also requires tuning and a complement of parts that work together.
What is your compression? Compression ratio? What is your vacuum? Did you advance/retard your cam timing? So far, this is a guessing game because we need to know a lot more.

Your 390's displacement is really 4.05 + .030 = 4.08/2 squared X pi X 3.784 X 8 = 395.8 cubic inches. That engine should roar like a Chevy 396, if properly tuned. - Dave