mercury engine

ron hebb

Member
1953 mercury engine 4 inch crank wondering what would be the right heads or the numbers on the heads




any help would be appreciated
 
Original heads have "EAC" cast near the center. If you have "EAB" heads, all the better. They give more compression and were a common swap back in the day.
 
EAC heads should also have the Mercury name on them. EAB are Ford types but they do have a higher CR for the 239 CID. This makes them even higher CR for the 255 CID Merc engines. The EAC would be OEM on a Mercury if that's the way you want it.
 
My wife's barn truck, the '34 pickup, has a Mercury engine with an EAC head on one side and 8BA on the other. Smoothest running flathead I ever owned!
 
So, how do you know it's a Mercury engine??
I believe the shop that built the truck for the seller that the engine is Mercury. It does have the 4" stroke. Is there something else on the block I could check to verify Mercury versus Ford. Not that it matters on our barn truck.
 
All USA cast 8BA blocks are pretty much the same with only a few exceptions. Valves changed to rotator type in mid 1951 and exhaust valve seats were the only ones with hardened inserts. The casting for late 1951 had 1BA casting mark down in the intake valley. Later in 52 or so, they did away with the valve seat inserts for car engines. Only the truck blocks continued to have the hardened exhaust seats.

The only difference between the Ford and the Mercury internal moving parts was the crankshaft, cam, and the pistons. Everything else was the same. When you change to the 4" crank, 1 of 2 different cam shafts, & use the pistons for 4", then you have a 255 CID Mercury short block. A person would have to use the oil pan, heads, intake manifold and maybe the front timing cover to have a built up Mercury engine long block.
 
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