Engine Serial Number: GEA717

This Serial Number ID page from the spec. manual is hard to read.

However, assuming that is an original code (and, it looks original):
GEA = 1949 5000 or 6000 series low-pressure 235 truck engine
717 = should be a number larger than 1000?; but, let's assume it means the 717th 235 out the Flint, MI engine plant in 1949?

I cannot clearly read your head casting codes.
head date casting code is under the valve cover.
head casting code is outside the valve cover.
Please post those two codes-numbers.