The Stovebolt Site Forums The Shop Area Engine Shop 235 "M" block?

I appreciate everyone's knowledgeable responses to my recent questions. Being recently new to stovebolts, I've been learning.

Can you take a look at the following pictures as they are from my recently cleaned up 235. I'm wondering a couple things:

Does anyone know what the "M" means cast into the block below the "3769716"?

Pic 1

Can anyone advise what the other cast markings mean in the block?

Pic 2

Pic 3

Pic 4

Pic 5


I do know the engine is a 1960 235 from a truck, but would like to know what the other casting marks mean.

Thanks.
James

Pic 4 E 20 0 should be the date code of May 20 1960. no clue about he M.

I believe only Canadian engines have that M on them.

I think that was made at MacKinnon's in St Catharines, Ontario. It was a GM engine plant. My uncle worked there for many years.