Back in the late 1960s if you wanted to buy a car in Canada, in most cases, it had to be built in Canada. This was before the NAFTA Free Trade agreement, and it's just the way it was. It would have been prohibitively expensive to build dedicated factories in Canada for every make, so companies like GM economized by building multiple vehicles on the same line. To make that feasible the cars would share chassis and powertrain, and even most of the interiors. Only the exterior sheet metal and the dashboard would be truly Pontiac, and the rest would be Chevrolet Impala. It was a forerunner in many ways for how marques share platforms today. This means Pontiacs delivered in Canada during these years used Chevrolet Impala chassis and powertrain, and so any engine that could be had in the Impala could be ordered in the Canadian Pontiac. It also means that the top powertrain option, the L36 427 Cubic Inch, 390 Horsepower TurboJet, straight from the Corvette, would be available in the Po