8BA or 8CM

Lyle

Lyle

Senior Member
OK i have a engine with one Mercury head and one Ford head.Stock automatic transmission. The intake has a Ford 3 stud carb. This leads me to beleave it is a Ford and not a mercury. I did not see the auto it came out of. I was told it was a ford convertable. Did ford instal a factory auto.transmission I thought Mercuru was the only one with them.Is there a marking on the block visable without removing heads or intake.I wont to change to both the same heads. I need to know witch head to pull I do not wont to remove both of them. What you all think I am leaning toward pulling the mercury head and checking the stroke 4'' or 3 3/4. thanks lyle.
 
1951 was the first year for the automatic trans in Ford & Mercury. Ford-O-Matic & Merc-O-Matic. I would pull the Merc. head check the stroke then use the 8BA head, it will work even if it is a 4" stroke, just a little more compression. I had one like that, 51 Ford-O-Matic with Merc. crank & 8BA heads , 8BA cam, one 3 bolt 8BA carb, great running setup.
 
Ford started using automatics in 1951. I believe the combustion chambers are different for Ford and Mercury because of the longer stroke. You will want to match the heads. It is probably a Ford crank because there were so many more of them. Just the odds. What does the Ford head say on it? EAB were from the later 52-53.
 
The 8BA and the 8CM Heads have the same size combustion chamber either head will work. All that changed fro Ford to Merc was the stroke as per Mr. Hurley. Thus the Edelbrock aluminum heads will fit either as per Mr.Edelbrock
 
Ford made different clearance volumes between Mercury and Ford engines to compensate for the longer stroke on the Merc. They end up with the same compression ratios by design. If you put the EAB heads on a 4" stroke motor, the compression ratio will be higher than a 4" stroke motor with any of the EAC, 1CM, or 8CM heads. I have measured 8BA and 8CM heads and they are not the same. 8CM has more clearance volume than 8BA.
 
Would it be better to run with thelower compression mercury heads BCause THE squirle piss they call gasoline. Is not as good as it once was.Iknow because I make the stuff.. I Have listened to others that have to purchase octaine boosters.
 
Lyle said:
Would it be better to run with thelower compression mercury heads BCause THE squirle piss they call gasoline. Is not as good as it once was.Iknow because I make the stuff.. I Have listened to others that have to purchase octaine boosters.
Click to expand...
Run the Ford heads. 87 octane will work just fine.
 
OK i am going to pull the mercury head and run both ford heads even if it is the 4" stroke. I also have a good 53 mercury needs a ring job I am saving this engine for a rebuild. Going to sink a bunch of cash in this one.I dont like the 2 stromburgs setup form just what I have seen and heard about them. How about A big ford 390 2bbl carb. I think this will be one of those (like the old woman that kissed the cow. It just a matter of tast)things. what do you all think. I dont wont a real ROMPER STOMPER but a little more than stock .Dressed up real as they say in East Texas (Purdy):):):)
 
That means I will have to find a 4 bbl intake. What brand is best I have headers on the 52 highboy A roadster. Running pipes no muf.
 
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