Engine Locked Up

[69 C10 LWB]

I just bought a 65 C30 knowing the engine was locked up. I have a spare 350 I can drop in but Id like to get the 230 running if at all possible. The guy I bought it from had dumped some tranny fluid in the cylinders. I have sprayed Seafoam Deep Creep into the cylinders 3 days in a row now. Yesterday I changed the oil (using spare oil and a filter someone gave me) and primed the engine with a drill. I had oil come out of a couple pushrods and the drill built up some torque so I know it was pumping. The top of the head is clean and I stuck a bore scope in the cylinders and they look good. I tried to bar the engine over through the starter hole but no luck. Then I decided to give it a little more incentive. I pushed the truck with a track loader and let the clutch out slowly. When the clutch grabbed it drug all 4 rear tires. I think this engine may be a lost cause but I still have a little hope.

Does anyone have any suggestions on other things I can try? My next step is to yank the engine and pull the pan off but there's a good chance when that happens the 230 wont go back in.