318 with 340x heads sluggish

I recently purchased a 73 Scamp that was mostly redone. The problem with it is that it is very sluggish even though the engine wants to go. The person I purchased the car from and his mechanic blamed the stall for this. He originally installed a new converter with a 3400 stall and then updated it to a 3000 stall. Its still slow.

My question is would a 2200 stall improve the get up off the line? Or is the rear end the issue? Or do I have multiple issues?

Not looking for a drag car but not a cruiser either.

Specs:
318 with 340x heads bored 30 over
mildly Aggressive Cam (do not have the specifics on lift)
performer intake
650 carb with 750 jets
Hooker Headers
904 trans (no shift kit)
3000 stall
8 3/4 rear with 3:32 gears
18' wheels