Bought a crowbar and finally got the stuck exhaust manifold off. Not exactly the way I was hoping it would come off, but at least it's off. If I had the spare change I would upgrade to headers, but as a poor college student I'll just be replacing it with a standard exhaust manifold.
After the exhaust manifold was off it was real easy to unbolt the heads, thankfully. However there was a lot of coolant pooled on a couple of the piston heads. Pictures below show their condition. Pistons 5 and 6 both are really discolored and had pools of antifreeze in them. I'm no expert but they don't appear to be cracked, so I may just roll with them.
Heads go off to the shop tomorrow to be cleaned and machined, so hopefully I'll have a running truck in the near future. Yellow jackets are out, and I even had to crush a small nest they were making under the hood, so getting this engine back together will hopefully happen soon.
On a side note, at top dead center, my distributor rotor was pointing at the number 2 spark plug. But in all the videos I have watched, it's supposed to point at the number 1 spark plug. Should I try and put the distributor back in pointing at #1, or put it back how I found it at #2?