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The head is the "848" 235 head that came out in '56 or '57 or thereabouts and became the standard replacement head for all '54+ 235's. It produces a bit higher compression than the earlier 235 heads.

The block casting date code (L313) shows that the block was cast on December 31, 1953. The last part of the serial number (F54X) decodes as:

F=Flint engine plant
54=model year
X=regular production "Thriftmaster" 235 from a 3100 series truck.


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