ID THIS BLOCK

Good Day All
Acquired an engine that was alleged to be of 1966 vintage. The motor had all the machine work done, just never assembled. All the new parts were there and the price was reasonable $300.00 it also included a transmission.
I was skeptical when I saw it but purchased it anyway.
So far I have determined that the head (4104363) dates 81-87. The crank (4095246) dates to 81-87 The block, however, is a mystery. Here are some pics:143.jpg144.jpg147.jpg145.jpg148.jpg More questions to follow once I figure this out.
Thanks to all who respond
'64 Dart