My manual from GM of Oshawa Canada shows the 235 full pressure Powerglide starting in 1951. This same motor continued to 1953 and then there were changes in the head etc. for 1954. Now I would doubt that Canada had that motor two years ahead of the US although there may have been some scheduling differences.
Another point of interest, some of the Canadian 216s used the same head in 1951 with the short side cover and a feed to the rockers from the rear gallery. This same 216 still had the low pressure arrangement with the oil distributor valve on the side but no external plumbing for the rocker supply.
