Identifying a Cdn Mercury Flathead Heads
 

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

Re: Identifying a Cdn Mercury Flathead Heads
 

not sure what you want to know but the blocks are the same as fords although i have heard some of the canadian blocks have better steel content. heads aren't worth much unless you are rebuilding and want everything stock. the only difference is the 4" crank and pistons and i think the merc cam has a little more lift than the ford. people want the cams and the cranks and the pistons. i guess it depends on what you want to do with the motor and how much you are spending on it. i just got a 51 or so merc motor and i paid 300.00 for it. the block looks great and the crank looks standard. it came with a 53 F100 truck.

Re: Identifying a Cdn Mercury Flathead Heads
 

F1 thanks. It is good to know what you paid. I have a 40 Ford & I am investigating building an 8CM 276 flathead.

I was asking about the Canadian heads as some are different & may have better compression. I saw a set of Cdn Mercury C8CM-B aluminum heads & was questioning if the C8CM-C are aluminum. Some of the aluminum heads had higher compression but that may have been just with Ford and not Mercury's. The only way to confirm if the crank is a 4" stroke would be to open it to determine the stroke to make sure that it is not a Ford block under all the Mercury parts.

There is a some thought that the Cdn blocks may have better metal. The odds of a Cdn block being cracked is still high.

The Mercury has features similar to Ford 8RT truck engine in that it has a bell housing that can be adapted to other transmissions, has rear oil sump & with the bonus of the 4" stroke. The Mercury has all the parts to be a good start towards a 276. The only way to be sure of the crank is to pull a head to measure the stroke. A head with compression would be too lucky.

It is too easy to spend a lot of money looking for a good block if it takes buying 2 or 3 to find a builder. Flatheads are expensive enough to rebuild w/o spending a lot up front to find one.

Glenn

Re: Identifying a Cdn Mercury Flathead Heads
 

Hi all; Here in Oregon we get a lot of Canadian cars ect. My set of aluminum C8BA heads are almost identical to a set of Elebrocks. later Newc

Re: Identifying a Cdn Mercury Flathead Heads
 

If you are trying to increase the comp. ratio, use the Ford EAB heads. They have a smaller combustion chamber than any of the Merc heads.

Re: Identifying a Cdn Mercury Flathead Heads
 

Hi Rick,

Just curious, how did you find out the EAB heads are higher compression? Any idea what vintage they would be? Reason I ask is I am going thru the process of figuring out what engine I have in my '49 F-47. It's a C1BA block with EAB heads.

Look forward to hearing about the heads.

Thanks

Re: Identifying a Cdn Mercury Flathead Heads
 

When Mercury used the 4" stroke, Ford did not want the Merc compression ratio to be higher than the Ford- soo the combustion chamber was enlarged in the Merc heads. That's how it is explained in old posts here on the 'Barn' I used to scrap EABs, until I learned!! Newc

Re: Identifying a Cdn Mercury Flathead Heads
 

Thank you, good to know.

Re: Identifying a Cdn Mercury Flathead Heads
 

I found this in my stash of pics.... don’t know if it will help you..... Mark

Re: Identifying a Cdn Mercury Flathead Heads
 

As mentioned 8CM or C8CM (or later replacement C1CM) heads would have the larger clearance volume for the 255 CID to have the same compression ratio as the slightly smaller 239 CID engines. Canada used aluminum a lot more since most Ford US heads were cast iron. There were high compression heads made for Ford US production and they were referred to as "Denver" heads These had a suffix with an S at the end (likely for special option). The basic part numbers were 6049 and 6050 for right & left. There were different oil filter canisters used in some cases that changed the first suffix letter after each engineering change. I think the Denver heads would have been 8BA-6049-AS for a right hand head but I don't think they made these for Mercury cars or trucks. I don't think they made any in the EAB years.

The EAB heads starting in 1952 were a step up in compression due to the more modern fuel blends that were available by that time and FoMoCo was trying to keep up with the OHV engines that the competitors had. The EAB camshaft is a good grind for higher torque and was the replacement camshaft for all earlier cams for both Ford and Mercury although the 8CM cam wasn't bad in it's time.

Most of Canada's part numbers were in line with Dearborn's numbers but they always put a C on there to designate where they came from.

Re: Identifying a Cdn Mercury Flathead Heads
 

Excellent! Thank you for the detail boys, much appreciated.

That chart is great, glad my engine came with the EAB heads. I still might look for aluminum "speed" heads but happy for now with these.

Now I need to figure out why I am only getting 40-45 PSI cranking compression. This probably is also why manifold vacuum is only 16 "Hg. This is cold, the engine hasn't run for more than 30 seconds at a time in the last few weeks and I don't know when it was last run long enough to open the T-stats. I am building an exhaust system for the shop this weekend to extract the fumes from the headers so I will be able to run it long enough to warm up.

Cheers