markings

[Sanddoc]

Hello
I see a "52 flat head" on CL
he says it's a Merc, but gives no other info.
He does show a picture with a stamping of 52 in a square and a
2 H next to it.
Any Idea about the engine... it's been dissembled I did count
24 studs, and no extended bell-housing
thanks

 

[51 MERC-CT]

The numbers don't indicate the year.
It's weird because of the head studs installed.
It may be a Merc. engine based on the 1CM stamping on the crank.
If the carb. and heads are original it's not a 52'.