I have run into these in the past. Generally is has something to do with the rubber sealing ring sticking in place. Iff'n it don't turn, then you have to bring it up a bit. Ib the past, the WD40 and such solvents only aggrevate the situation fo they attack and swell the rubber seal.
I tried using a crowbar one, but seemed to be of wrong length. Was planning on resting it on the C.I. manifold lip, then the tip underneath the Dist. body.
Best system was to use two or three good flat blade screw drivers. Just whack the thin end down in between the C.I. manifold, and the aluminum lip from the distributor. Then another in the gap. Push down, pry up just a bit. Only need to pry up maybe .020" and then things ought to rotate. You may then need to pry out even more for there is often goo as in old dried oil collected on the tight fit in the block.
Wm.