Can you believe I am posting a topic that is not about lowered and piped Chevys or radial wide whites?

I don't even think there will be much controversy with this one!
Here we go, got a phone tip on a motor that came out of a 37, and I got some numbers and info (over the phone), so I am not sure where or how these numbers are on the block:
941 / 838841 / 21CD199 / 23167
It has "one water pump outlet" and a "2 bolt main instead of 4 bolt main at the rear of the engine", suppossedly earmarks of an older block (?).
What might we have here, please let me know, thanks!