yo HAL,
WELCOME!
I usually use a scratch awl and remove as much corrosion between the distributor and the block as I can, then use a huge adjustable wrench to turn it after dousing it with Kroil.
I used some pb blaster and a little knocking from my hammer and it budged.
Mix a small bottle of 50/50 ATF and acetone (nail polish remover is made of acetone)
taped it around with the BFH pretty hard, but I was planning to replace it anyway
Some tips from other 78/79 Bronco owners;
Didn't want to use a torch for fear of damaging plastic parts. Used oil and a 12" pipe wrench (instead of water pump pliers, because it grips/bites harder when turned) a cheater pipe and lots of gentle tapping with a BFH. Didn't make the dizzy housing shaft any prettier, but it came out and sandpaper smoothed most of the marks.
