Unsticking an unused engine........

It takes about 45 minutes to pull a small block out of an A body. It takes about 4 hours to install one. Just fyi. Instead of messing around with a stuck one (unless it’s a numbers 340 or something) I’d just swap it. Pick up a used long block for cheap and swap it out.
It's the original 273 Commando and has significant sentimental value, so not really an option. This one gets rebuilt. I know, I know... I'm a fool.