Don,
Here's a try at interpretation:
3835913 = 54/55 235 head
Head date: 913 = Sept 1 1953 or 1963? (2 bolt valve cover(1953) or 4 machine screw valve cover (1953)
3764476 = 56-62 truck block
Block date: A88 = Jan 8 1958
217 in the engine serial number location on the block?
Some sort of replacement-engine code?
Maybe others can provide better information?
