Jerry... is that an 850 head?
3836850 casting number
J 14 9 date code
Looks like a 1959 or 60 engine, but I haven't checked the block casting number or build date yet. I've got another late model 261 stashed away, also with the big oil gallery ports and an 850 head, plus two early 261's with the high mount water pump, and a 261 Canadian Pontiac engine.
Jerry