[Lynn Eades]

Scott have you tried turning it against normal rotation?
Has the gearbox had water in it? Is it the gear box that's stopping it? What happens if you try with the clutch depressed? Will the chassis roll with the gearbox in neutral?(main shaft still turns) Will it roll with the clutch depressed (clutch is free and the gearbox is all turning)
If it turns out that the motor is seized, put a little diesel in the cylinders, with a bit of rag. Light it and let it burn for quite a while. The thermal expansion will help free it up. (probably better out side) It only needs to be a small flame.
I assume this is a 216 and has cast iron pistons?
Try a small hydraulic jack with a block of wood under the exhaust studs. be careful. you might get enough purchase by hand with no lever fitted.