[rotorwrench]

It should be EAB. Ford was trying a new coding system in that time frame to the old system used in the 59A & earlier no longer applied. With 8BA the 8 represented the last digit of the year 1948 since that was the design year of the engine. What the B and the A represented, I'm not as certain but it could be for a V8 engined passenger car. If you look at the 8RT code for trucks you can see that they used the RT to represent a V8 engined truck since the R code represented V8 in the ID number where H code represented the 226 6-cylinder engine. Toward the middle of the 50s it started to use a different code. B was a code for the decade of the 40s. E was a code for the decade of the 50s and so on. Like anything, there are exceptions to the rule and with FoMoCo in particular there were plenty. Mercury cars beginning in 1949 were 8CM (designed in 1948, 255 V8 engine, and Mercury). In 1952 they changed to EAC for Mercury so you can see a departure from the old norm prior to 1952. This was the year that the first OHV 215 6-cylinder and the first Lincoln Y-block came out so things just kept changing after that.

There were no real changes to the 8BA block with exception to the phasing out of stellite hardened valve seats. The later crankshafts were changed to fit the big Ford-O Matic/Merc-O-Matic transmission components. Valves changed to rotator type, the cams changed profiles, and the EAB heads had smaller chambers. EAC Mercury heads still had a larger chambers for the 255 Mercury but there were other small differences.