[3macs1]

No I don't think that 454 would have a tall boss. It is not a tall truck block by any chance. Not all of them had truck stamped. They were 3969852 for the 366 and 3969858 for the 427 from 68-85. cannot see it if you raced it but just to eliminate another possibility. Easiest way to tell is how much material is there between the top of the water pump bolt hole and the top of the deck. Truck block cannot be missed when you look there.