Canadian Pontiacs, etc . . .
I think '64 was the year the Grand Prix had that beautiful concave rear window, although maybe '63 had it as well. Very elegant and made the car look like much more than a Pontiac, although a loaded Grand Prix cost a lot more than the average Pontiac as well.
Canadian Pontiacs are interesting as sometimes they didn't have an exact US equivalent, such as having high-line trim on a slightly shorter wheelbase. Engines were generally from Chevy not US Pontiac, and Chevy made better engines. I'm guessing that GM made most Chevy engines in Canada but not Pontiac engines.
One funny by-product of this was the Pontiac division "stealing" the original Camaro Z-28 engine from Chevy to go racing in the late '60s Trans-Am races. At the time there was a 5 liter limit (302 cubic inches) which worked great for Ford as they had a 302, this is exactly why the Boss 302 Mustang was created. Chevy's 327 and 350 were too large, and since GM didn't officially race Chevy had to use their limited racing budget to come up with a very hot under 5 liter engine. By putting an obsolete 283 crankshaft in the 327 block they made their own 302, felt by many to be one of the greatest Chevy V8s of all time. It was only available in the first Z28s, back when that was purely an option number and not a marketing name - hardly anyone knew what it was. Those first Z-28s are now quite rare and valuable.
Pontiac wanted to go Trans-Am racing too, but their 326 engine was also too large and a boat anchor by comparison to the Chevy, it wasn't as strong and weighed more. However, the Firebird was offered in Canada with Chevy V8s so the Pontiac guys simply submitted Canadian Firebird homologation documents to the Sports Car Club of American showing the 302 . . . supposedly Chevy in Detroit was just livid but they could do nothing about it.