How To I.D. a Merc Flathead

[RalphG]

He might mean “Mercury “on the heads.

I’ve had younger folks look at my flatheads and wonder why a six cylinder has eight spark plugs.

Yes, I just heard back and he says that Mercury is on the heads. Was that a U.S. Mercury thing? All the Merc engines I've seen here are EAC made in Canada on the heads.

 

[Alaska Jim]

I do not know if it was on all the U.S. Mercury heads, but I do know that it was on the 49-51 heads. also marked with either 1cm, or I think some were 8cm Mercury was in script writing, not block letters

 

[RalphM]

I’ve seen most Like this;