Date code on the block is 72-Nov-23. Hard to see if the last digit is a 3-5-6 or 8 but Nov 72 block no doubt. It could be a 428 or 390 block. Does not look like a 427. The heads are older 61 and the 3x2 setups are cool and period correct. Tell me is there a 352 or reverse 105 on the front left side of the block? 64 Gal is a nice ride too! Very cool.