My 383 is weak!?

if the compression is good and the ignition is tweaked like you plan, i would say the cam is too mild

also the 10:1 pistons... maybe they are spec'ed for 10:1 but if the block wasnt decked you might only be at 9:1 or even less, depending on which heads you have on there.

but really, the mopar rv cam is more meant for mileage and low rpm torque not big power.