I should go the PM route on this, but what the Hell.
That 455 must use an aaaawwwwffffuuuulll lot of gasoline pulling that big rig.
I don't know the price of gasoline per liter in Canada today, but when I lived there in 1979-1980, it was about 2 times the US price. At least that was less than the price differential for cigarettes and booze, that was killer.
In one of your photos appears a pickup that seems to have the same drive arrangement as the Olds. Was that a 4x4 with the back end drive removed? And do you know what make it was. Fascinating vehicles.
Bill