[Kurt in NJ]

Just because it is nos doesn't mean it is good, some nos parts stayed on the shelf because they didn't fit properly
A broken rod will stitch out a cam and the block
Since 7 was hitting try the other head and foil balls, clay and see it both heads have same clearance
What condition are the cam bearings--- a cam bearing failure could cause the oil pressure loss, and the cam loosing support of the bearing could break
A very loose rod bearing can let the pistons hit the head, but with floaters most likely it would be the pair on that journal---4-8
If the same guy did both engines find someone else for the next