[rotorwrench]

The best FoMoCo V8 L-head blocks were the early Mercury & truck blocks starting in 1939 but they are harder to find since the country was scoured over for them clear up into the 50s. This 99A block was the first 239 and was continued till the 19A block in 41 changed the design a bit & did away with the pan rail core sand plugs. The 29A block in 1942 was carried all the way through the war with improvements till the final improved version in 1945 was redesignated for civil production as the 59A block. The only non-improvement in the 59A was they didn't make the cylinder walls as thick as the pre-war motors (99A thru 29A). I think the 41A block may have been produced during the later part of the war (1944) as a replacement 221 block for all early cars with 24 stud heads but they were continued right on into the late 40s and even had the 59 designator on many of the bell housings.

In 1948 when the F series bonus built trucks started production, they had 8BA engines. 8RT has always been a designation for V8 trucks but the 8RT heads were a replacement part for the old 8BA designator in truck engines so by 1951 or so, all FoMoCo made for trucks was 8RT heads. The blocks are all the same no mater what the heads have cast into them. The 1CM heads were replacement heads for the older 8CM heads on Mercs. EAC heads can be used to replace 8BA heads since they are pretty close in CR. EAB heads are the ones most folks look for now in the 8BA family of engines.