It's a Canadian thing. 60's Pontiacs sold in Canada were built in Canada. Exception: 1st gen Firebirds were not built in Canada.
The Canadian cars were badged differently. For example, a Pontiac Catalina in the US was a Pontiac Laurentian in Canada.
The Canadian Pontiac's came with Chev engines on chev chassis's.

We called the orange blocks "small block" Pontiac's and the blue blocks "big block" Pontiac's.