More power from my 360 Duster?

WOW! Great advice here so far. Your combo is indeed a nice one. Good balance to it.

I have a question for you. (Or 2)

Would installing a higher gear ratio be out of the question? (IE; 4.10's)
That would get you moving in a hurry but limit your streetabilty's a tad.

Otherwise, I like the above Lunati or Comp hi-lift XE series cm swap idea.

The 625 carb is liveable, but a 750 would suite top end and full max output.
Your not really missing much with the smaller carb.