If your truck is a Canadian GMC, I suggest that you look up OldCarKook's website that is on the links here , OLdGMCTrucks,and look up Canadian serial numbers. I verified my Canadian 51 1 Ton GMC that way. GMC Canada used Chev engines in those days. There were no obvious external differences in the Canadian 216 and the 235s. The only difference that I know is that the carb throat had a slightly smaller inside diameter. As for age, the pre 1954 engines had a small oval shaped plate on the manifold side, about mid block and about halfway down. This is where the oil distributor valve was and the post 1953 engines were full pressure and did not have these.
