Full pressure 235's didn't exist in 1952- - - -more likely it's a 1962 production engine. Where does the water pump sit- - - -inline with the radiator, or a couple of inches low? How about the side cover? Does it stop below the spark plugs, or go all the way to the valve cover? A 1952 year 235 would be a spray-oiler with Babbit connecting rods, and it would be lucky to have 10 pounds of oil pressure at hot idle.
Jerry

Edit: I just noticed a PCV system- - - -start looking for captain's bars above the starter and in the middle of the block on the driver's side- - - -you just might have a 261 there! Are there a couple of big pipe plugs (1/2" NPT) on the driver's side down near the oil pan rail?

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!