The engine serial number decodes as follows:
F=Flint engine plant
129=build date=January 29
H="Thriftmaster 235" used in 31-32-36-3800 series.

The year would be '57 based on the block casting number (should that be 3837004?) and the format of the serial number, which changed in '57 (the tocmp site has an error regarding '57 engine serial numbers). The head casting date code B37 (February 3, '57--a few days after the build date??) confirms the year if it is the original head to the engine. The block should have a casting date code, too, probably by the starter.

Curt
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1953 Chevy 6400, 1957 Chevy 2dr Sedan
--"Mediocrity is easy, the good things take time"