Engine of barn find-steps to evaluate/save

RustyRatRod said
I agree with removing the valve cover. Then, just LOOK at all of the valves and see if there are any "short". That would indicate a stuck valve and might be what the piston is coming up against. If you find one, take some GOOD penetrating oil and spray into that spring and try to SOAK the valve stem where it goes into the guide. Let it sit a while and then come back, loosen the rocker adjuster, remove the pushrod (probably bent), push the rocker out of the way and tap the end of the valve stem and see if you can free up that valve. Tap on the VALVE TIP, and NOT the valve spring retainer.

A 225 engine is a "free wheeling" engine, the piston will not hit a valve even if the valve is stuck wide open. A one 170 is an "interference engine" and the piston can hit a wide-open valve. I never checked a 198 engine, so I don't know about that one. (I'm talking about a stock engine, here)
It is possible a valve is stuck and the valve train is keeping the engine from turning over when the cam tries to move the valve. I'm more inclined to think the engine might have a connecting rod problem. Where the crank hits the rod. But definitely check the valve train, first.