Just a SWAG, but isn't the time frame in question about when they started putting oil galleries for hydraulic lifters in all the engines they cast, whether or not they got a juice cam? Maybe a prototype for those blocks?
Jerry
You may well be onto something there.
In 1953, passenger cars which came with a Powerglide transmission came with a "special" engine, in that the 235 for those vehicles came with hydraulic lifters, aluminum pistons, insert connecting rod bearings, and full pressure oil systems. They had a set of captains bars cast into the block above the starter to designate them as "special" so to speak.
These captain's bars went away in 1954 even though the 235 engine remained pretty much unchanged.
