F1216J Is your engine code. Note, the letter "eye" is used as number "one"...it keeps number one from looking like a miss stamped number seven.
F = Flint Engine Plant
12 = Month (December)
16 = Day
J = Designation - 235 w/3-speed trans 3000 Series Truck (1/2, 3/4 & 1-ton). "J" was used from 1957 through 1962 and for 1963 factory 4x4's only).
I 3 8 is your Date Code.
I = September
3 = day
8= 1958
I believe B50 is the sand casting part number for that part of the head and it works with heads ending in 848 or 850...used by the foundry only...means nothing to us now.
So, it looks like your block was cast in Sept and built in Dec to go in a 1959 model year truck.
Mike B
