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.