Distributor filling itself with oil

La 360, been in the car for 15 years, about 20k on it. Has had stocke electronic ignition, then msd pro billet. After i removed the megasquirt and went back to a carb i wanted vacuum advance and easily adjusted advance curve. Went with an Amazon special hei style distributor.

About 200 miles in, it started filling the cap woth oil. Thats a new one on me. According to a Google search, this can be caused by too much crankcase pressure. However, ive never had this issue before with any other distributor, and im setup for crankcase evacuation exactly the same still. So it has to be the distributor.

Took it apart today, and see no actual seals between the body and the shaft, just bronze bushings. Same as the factory chevy hei i took apart today. So no smoking gun there.

Im guessing the hei is more sensitive to crankcase pressure than others?

Anyone ever dealt with this before and find a solution?