Wouldn't the overhead valve problem only apply if it has valve/piston interference? If there's no interference then the engine should technically still be able to run on the other cylinders. My dad once had a V8 with a valve stuck open and he kept driving on seven cylinders.
Unless the intake allows the spark to reach the manifold with a stuck intake valve. I remember my dad disconnected that one cylinder's sparkplug wire because he was afraid it would backfire up through the carb. Or maybe it was backfiring and wouldn't start as a result. I can't quite remember.
What I do remember is that it ran pretty well on seven cylinders, at least after he disconnected the sparkplug wire to that one cylinder with the stuck valve.
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