Thijs, I hope you got the information you needed.
I read somewhere previously that Canada GM did many things differently than US GM, including the short side (push rod) cover 216 which was never built in the US. Please post some pictures of your engine and truck.
I have a Canadian 216 with a short side cover. Although now rebuilding a '55 235 to replace it. Picture of the 216 attached (I think. Can't see it in the preview).