'63 and '64 Canadian Valiants had Dart bodies (111" wheelbase) with Valiant front clips.
The alternator was optional in Canada til '63, when it became standard equipment. Chrysler Canada had a contract with Canadian Auto-Lite (i.e., Prestolite) for a certain number of starters, generators, and distributors, and so Canadian-built Slant-6 cars got Auto-Lite starters and distributors through '66, Auto-Lite generators as standard equipment through '62. So that's one example of a specification difference in Canada. Another: the 318 Poly was kept for an extra year in Canada. Another: the 4-speed was available behind the 225 in A-bodies through '66. Another: the carburetor
anti-ice system that was standard equipment on US '69s and not available any other year in the US, was optional equipment in Canada from '61 or '62 through '68, standard in '69.
But overall, the Canadian cars weren't behind the US cars, they just sometimes had some specification differences.
You're mixing memories. The A-bodies in Canada had exactly the same heater setup as the US A-bodies, year by year. The '60-'62 cars had the heater box on the firewall, the '63-up cars had it under the dash. The '60-'62 Canadian Valiants used Valiant sheetmetal front to back, with only minor badging differences to the US model.