3835913 is the head casting code on a 1954 or 1955 first series 235 engine.
F54M as part of an engine serial number would indicate a 1/2 ton 1954 (3100) truck made in Flint, MI and having a Hydra-Matic (automatic) transmission. Can you post a photo of that plate? It might be an engine code plate that was at one time attached to the Hydra-Matic transmission (the Hydra-Matic's engine and transmission were matched at the factory).
