HEI acting like a rev limiter w/ video

I've got a problem that I think is originating in the ignition system. When I stab the pedal there is a split second bog then revs fine to 5000 when I pull my foot off. But when I rev the engine up slowly it will go a little past 2000 then drop to back to 2000 and sit there sounding like a rev limiter and the tach needle quivering even though I am still moving on the pedal. After a couple of seconds it will begin to rev up again. I've disconnected the tach to see if that was the problem but it was the same.

The ignition system is a standard type Mopar distributor with an HEI 7 (8?) pin module and coil. Ballast resistor has been bypassed. Engine is a 1990 360LA. Internally stock but has a performer manifold and 4bbl Holley and headers.

I'll post the video as soon as I figure out why I can't get it off of my phone...

Let me know what other info you need. Thanks!