Ok-- here is the scoop on your engine 3837012 was a 216 built in 42-51 and someone was having fun playing with the serial-- the original serial is under side cover in the right lower corner surface --none there -- then it was a replacement --look behind the starter and the casting of letter --number --number such as
A 14 6 would be Jan 14 1946 last number is the year -- Beck's --