Engine Wants To Cut Out At 2000 Rpm On The 66

My engine is a 302 roller rocker with flamethrower coil and pertronix billet distributor. The car idles around fine but when I get on it there is a popping sound small pops at 2000 rpm and beyond and wants to stall. I checked vacuum with a gauge and she's steady as a rock at 19/ 500 mm Hg. So no sticky valves or vacuum leaks or similar problems. The carburetor is a Holley 650 double pumper that was very recently rebuilt. Could it be carburetor troubles? Blown power valve? I am considering getting a new Holley 650 with all the technology built into it. Or is there some other problem? Any suggestions welcome.
Thanks,

Richard E.

Bought myself a new Holley 650 Double Pumper no choke horns, stainless steel lines to carb with aircraft style blue and red fittings and an Aeromotive fuel pressure gauge. Car needed this treat. Will see if it irons out the problem. It's gonna look awesome. Four corner idle adjustments too!