I really wish I had more time. I still have that Pontiac 400 seized complete engine. I expect it to be in just as bad of shape as the 425 Olds engine was. Now the Olds 425, I had gotten apart. I had soaked that thing in everything imaginable for several weeks to no avail. It was not coming apart by soaking in Trans Fluid, PB Blaster, Acetone/T Fluid mix etc. So I cut 3 of the connecting rods with a SawzAll to get the crank out of it, then beat like hell with a 3lb 1/4 jack hammer to get the pistons to slowly budge. Very sad, but the motor didn't even need a bore. Had it not seized, a ring job would have been fine. There was no ridge at all in the cylinders.
So the next experiemnt I want to try, is to disassemble the Pontiac long block down to the short block. I now have a heavier duty charger. Its a 10/40/160. Where last time I did the project on 10 amp, I wast to do it this time on 40amp. I also want to leave the crank and pistons in the block this time, and see if after the process is done, if the pistons will actually break loose and unseize the motor. It would seem to me that is should work. The only thing keeping the pistons from moving, is they are basically rust welded to the cylinder bore. Take away the rust, theoretically, the motor should then be unseized and then be a rebuildable virgin core.