Identifying a Cdn Mercury Flathead Heads

[Patterg2003]

I have found a Canadian Mercury 255 flathead engine with a block casting ID of C1BA which is a Cdn 1951 Ford & Merc block. He said the casting letters on the head are C8CM-C. I have seen Cdn C8CM-B heads but no -C's yet. Could the -B's be equal to EAB's and -C's equal to EAC's?

The engine is a day's drive so I am trying to learn as much about this engine as possible. I know that a CB1A block could have been switched in its life so it could be a Ford 239 block. I have been learned a lot on buying a flathead engine from the Ford Barn & the HAMB so approaching this with extreme caution.

Any information on these C8CM-C heads is appreciated. Are the casting letters different for aluminum heads?
Thanks
Glenn