They were made briefly in the U.S. only around 1950, but in Canada they made sedan deliveries through 1958. They are rare and are basically a Chevrolet sedan delivery with Canadian Pontiac sheetmetal.
That particular 57 has got a stock 261 Pontiac inline six, which is the Chevrolet truck six but with hydraulic lifters as well. They were silent at idle and strong for a six.