I appreciate everyone's responses-

I tore this down over the weekend and pinpointed what was wrong-

Several bent INTAKE pushrods and one broken Intake rocker arm on the #5 cylinder. Several intake valves apparently stuck.

So, this is actually an intake valve and not an exhaust.

I forgot to get the casting #-I will take a picture tonight.

Thanks!
Keith

1951 3600 Chevrolet