The carb seems a little big for the cam, cubes and stall. I'd try a swapmeet 600 Holley since they're cheap to find. Switch back to the 750 when you do track time with the nitrous.

Do you have the valvesprings to compliment the cam?

Is that a calculated compression? How much is the piston in the hole?

R.I.P.- Gary "Coop" Davis 02/09/68-05/13/04