10M made in Canada heads
 

Never heard of them before.. Anyone know about them? Steel, Aluminum. volume etc

Re: 10M made in Canada heads
 

That should be 1CM, cast iron head. Not sure what they cc at.

Re: 10M made in Canada heads
 

The numbers on the heads usually begin with C in Canadian production. In the 8BA era, they generally follow the standard Ford prefix number/letter coding with the exception of the C at the beginning. They did make aluminum heads in that era too but they were generally special purpose items. A person also has to check the suffix. "AS" was a Ford suffix for special purpose items like the Denver high compression type heads. A lot of the Police Package engines used them.

In the US, the 1CM heads were a replacement for the older 8CM parts for Mercury cars. In 1952, they changed to the EAC prefix for the Mercury. All Mercury heads had a reduction in the chamber volume to make the increase of cubic inch displacement balance out to the same compression ratio as the 8BA Ford engines. Ford didn't take any chances on compression ratios due to the wide variation of fuel quality at the time even though it was getting better than it was before the war.

PS Chamber volume was Increased not Decreased for the Mercury per post 5. Brain Fart! The reduction was in compression ratio to match the Ford 239. Good catch.

Re: 10M made in Canada heads
 

1CM is 1951 Mercury, 255 cu in and 6.8 to 1 comp ratio. Canadian engine would have C1CM which is same head

Re: 10M made in Canada heads
 

The Mercury heads did not have a reduction in chamber volume. That would have resulted in an increase in compression over Fords. Mercury heads had an enlargement in chamber volume, to reduce compression to be comparable to Fords.
Mercury's larger displacement over Fords gave it higher compression.