Help identify what engine in a plymouth 1937 flathead 6 stamed serial under water pump M19310 on please???

[Pat McCabe]

Serial number that starts with m19310

[Bryan]

Flathead Six Engine Numbers (t137.com)

[Pat McCabe]

Hi Bryan,I have that link,but theres no stamp that starts with M thats what is throwing me off here,Thanks

 

[kencombs]

'under the water pump', not the normal place for numbers.  Look on the left side of the engine block, front, above the generator right at the top edge.  There should be a machined flat spot with the real ID numbers.