If I could bust out 8 pistons out of Joe's rusted up 400FMX block you can get a piddly little distributor popped out.
Heat works, the problem is that iron and aluminum don't play well together, the weaker metal (aluminum) will oxide and cause your stickage, throw in the fact that the dizzy is in a location on a Cleveland block that traps water, and you have yet anther bad actor in your story.
So toss in our hero Mr. Propane torch, and Ms channel lock. it should come loose, if not then move on to MR BFH and his sidekick "chisel".
If all else fails call a few friends over, they will each have a go at it until it comes out, thats just how we car guys are, we won't be beaten by something as puny as a dizzy.
Buck up cowboy!, grab a 12 pack of cold beer, head to the garage and remove that F#%!@'n distributor!
if you destroy it in the process, all the better, now your budget director will understand your need for a shiney new one.

Blizz
Another idea;
To remove brass Propellers on PT Boats and river patrol boats, my friend from college who was on board one in 69-70,told me they would go overboard and remove the nut, then wrap a strip of det cord around the shaft, it would pop the prop off into the mus below, and then they would re-install a new one and be back underway.
With the prices of brass and bronze nowdays, anyone want to take their metal detector to SE Asia and search for props?