Mercury ID help

W

Wrenchead

Junior Member
I recently acquired a Mercury flathead and would like to know the year and specs.
Here are the numbers/letters so far:

Head:
F L
EAC
C 18 3
Mercury
12

Top of rear of block:
24
39 x : 4

Intake:
8 B A 8 R T
6520

Rear intake top of right side of block:
3 C
 
Hard to tell what you have because the head and intake contradict each other. The heads are for a '53 Mercury, but the intake is for a Ford (car or pickup). You are probably going to have to take a head or oil pan off to measure the stroke to be sure. The only thing that is really important is whether you have a 3 3/4" or 4" stroke crankshaft. Other than that, the differences are minor.
 
If heads are original the EAC heads were 1952/53 production but they are easily replaced. Measure stroke or width across the crankshaft counterweight cheeks. Some crankshafts have casting marks with the prefix but not all. The 6.5" width across is Mercury. All of the 8BA blocks are basically the same with the exception of the valves beginning in 1951 plus the obvious crankshaft & pistons mentioned previously. Rotator valves and a larger crankshaft flange bore were late engine characteristics and also the elimination of hardened intake valve seats and exhaust valve seats on some engines. Many late engines have a 1BA casting mark down in the tappet valley area.
 
Last edited:
As stated until you can determine if you have a 4" stroke, that will at least tell you that you have a Merc. crank. For now it appears you may have a Ford block with Mercury heads and possibly an 8RT truck intake.
 
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