It looks like the first three digits on the Engine Serial Number is "236".
On many GMC engines, the first three digits is the engine displacement.

236 GMC Engine
GMC also developed an OHV/pushrod engine in 1939. The 236-cubic-inch (3.9 L) 236 was produced through 1942. This is a low-deck engine. The bore was 3.625 inches (92.1 mm).

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.