[ford38v8]

Mickey, if the L is large, and immediately below the 59, then it is is what is known as a 59L block. A much smaller L, grouped with other smaller casting numbers would not have significant meaning.

59L blocks were produced in the 1945 and later time frame, some were military, some commercial, and some were replacement blocks. Most if not all 59L blocks were factory relieved. The fact that yours has A heads may mean that it was a replacement block, as the A heads were earlier.

It would be interesting to know if the A heads on your engine had been flycut to accommodate the wider stance of the later valves, of if your block had the earlier valve configuration.