I have removed many. Don't use channel locks or anything that would gore the metal.

I used a 1 inch wooden dowl and hammer, on the hold down loop part of the distributor, where the bolt goes into the block. That moved it. I kept doing it. I got it up sufficiently to put a screw driver between the block and the elongated hold down loop, prying up gently and twisting. They get rusted in there and the oil that bakes around the barrel exaccerbates it.

Anything else might damage the distributor.