Thanks for the input everyone.
The thing is and I could be way off but I figured since this is a horizontal cylinder motor, there was no way I would be able to get any "juice" up to the top of the cylinder where it's really needed. Especially with the sparkplug hole only about halfway up.
After that first week of messing around with it, I've taken the head off and have been heating, spraying and tapping on the top of the pistons with a block of wood and a two pounder every day. One piston gives a dull thwack sound so I think that one is somewhat loose. The other rings like a bell. Just sounds tight in there.
Right now the plan is to disconnect one connecting rod and turn the crankshaft to push the block forward off the main case with the stuck piston in it. The disconnected piston/rod assembly will ride along in the block as well. At this point I should be able to get to the bolts to remove the other connecting rod.
Then at least I can get the block out of the tractor and orientate it with the cylinders and pistons pointing up. Then whatever cocktail of stuff they say works will reach all the way around so to speak. Also, it'll be much easier to swing a 16 lbs RBFH if it comes down to that.
The other tractor may be a lost cause. I knew the block had been very obviously brazed a number of times. It wasn't till it was on the trailer and out of the rattlesnake infested grass that I saw the bottom of the main case has been blown out with frost.
I was willing to do another block, but the main case is a death sentence, I think. It does have some good parts on it, a full set of shutters, electric starting motor, lights, etc.
I need to get this first one apart first as I don't even know what oversize pistons to start looking for even.