I'm going through the same identification issue with the engine in my 1951 4400. The problem is complicated by the fact that its a re-manufactured engine, most likely a 1954.

The 3836848 cylinder head casting number is one that I did a lot of research on yesterday. These seem to have been the heads of choice because they had a slightly smaller combustion chamber than the others. Higher compression ratio = more power if it doesn't have pre-ignition problems.

195? Chevy 3800 dump truck
1973 Chevy C30 cab and chassis
1987 Suburban 3/4 ton 6.2L Diesel