casting codes

[bucketobolts]

I'd say you have an early casting 302 block. Should have the standard 8.206 deck height and 4.000 bore. Should have came with a passenger side inlet water pump, dipstick provision in the passengers side of the block, and a 3 bolt 28oz balancer. My guess is that at sometime or another this motor was swapped into the Bronco just because of the date code. Though the Bronco line seemed to a lot of Ford's left over parts. The only special blocks from the '60's would have been the 289HP(C5AE-E) or the 4 bolt main BOSS(C9ZE, D0ZE), but even then the HP block was standard issue with beefier main caps.

[bucketobolts]

Do you happen to know the code on your heads? It is on the bottom side of one of the intake runners facing the lifters. With the heads installed and intake removed you can use a mirror to look up at the code.