OK, it's off. Heat WAS the answer. Enough heat was the secret. It's the PTO pulley from a CC149. The engine's blown and I'm salvaging what I can from it. A gear inside let go, evidently, and blew the side of the block out where the starter/generator bracket bolts on. Kinda kool, since it wasn't mine until last Sunday! Got the tractor, mowerdeck and snowthrower for $375. If this were something I planned on doing more often, I'd buy the proper puller, but to be honest with you I'm not sure what the proper puller even looks like. I ended up supporting the engine from under the pulley with 2 steel bars between 2 buckets, heating with a propane torch and whacking on the end of the crankshaft with a plastic mallet. Minimal distortion of the pulley and surely not enough heat to hurt the crank.
I'll be watching for Kroil, now, and getting a can when I find it. Might have to keep it locked in the safe and just use it for special occasions! More used to WD-40.
The reference to set screws hit home. This time they were both out, but I've been known to remove set screws that were being used to lock the "real" set screws. Actually, that was on the PTO clutch on a CC105. Expensive lesson. I call it "tuition".
Anyway, thanx, all, and if anyone needs parts for a K321, I've got some!