Just got my new engine fired and it runs great! The only complaint is when I rev it up, its not as crisp sounding, as I'd like it to be. I run the timing at 12 btdc and 35 total in by 3000 rpm. Carb is 600 holley Double pumper #4776 out of the box. All those pump cams and different holes, confuse me and I don't really know where to start! Here is the combo- 355, 10-1 comp, RPM heads 64cc, single plane intake w/divider, cam is crane 274, 218 @.050,.450, 106 separation, 1 5/8 Headers.
Thanks!

I figured it out and the car runs great! Went to a #25 squirter(down from a #28) and the pink pump cam in the #1 hole position. 66 and 73 jets.

Sorry I missed your post earlier, but glad you figured it out. A smaller squirter seems to be a pretty common fix with the double pumper carbs.