Hi Albert, answering quickly off the top of my head, which is never a good idea without cross referencing, but there are two types of aluminum used on our motors. One trademark is lynite, which was produced in New England, and the other was Tenual, which as I recall was produced somewhere near Cleveland. A lot of cases outside the US seem to be marked Tenual, and altho I think noone has a definitive answer, it is possible that the tenual castings were shipped into Canada  and overseas from there to avoid British Empire Import tariffs, or maybe simply that one aluminum foundry could not keep up with demand, so they had to have an alternate source.

Will try and look up my notes on the company that produced tenual over the weekend.