[blucar]

The 59 AB engines, which ever year they were made, have always been the preferred engine for re-powering just about any early Ford V8, '32/48.. Some people don't care for the low mounted distributor.. I have been running one for almost sixty years and never had a problem, that is except for them being prone to wetting out in heavy rain and/or trying to ford a creek on a fishing trip.
"A shot of white gas in the distributor will drive the water right out of the ignition". Learned this from my dad in 1946 when we got caught in a flash flood..
It is a common held believe that the majority of the early Ford flatheads, '36 through about '51 had hardened valves/seats. It has been reported in several texts that Ford discontinued the hardened valves/seats in the 8BA/8CM engines starting sometime in '51/52.
The placement of the distributor on the 8BA style of engine makes the unit more accessible, however, it interferes with the placement of original accessories, gen/fan, etc. Reputedly the 8BA engine have an improved cooling feature designed in to the block/heads.
The 59 AB engine is a direct swap into the early Fords, '36, etc. The 8BA's require a combination of '49/50 Merc and/or Ford F-1--3 truck parts... Namely the bell housing and water pumps... The Ford cars 49-53 do not have motor mounts built into the pumps.