I don’t know that there are any mods for the engine as your Canadian gmc is basically a Chevrolet .If the engine is a early 235 the water pump is in the same location .If you buy this check the casting numbers to see the year .My 54 needed a new motor when I got it And should have had a older 235 but when I got the short block was given a newer 235 ,it fit the only mod that may be needed is the water pump relocation plate.I have been running it without any mods for years without any problems .If your engine is okay then just change it but FYI there is not much difference that I know off.
