Tim,

The oldgmctrucks.com link gives the Canadian series numbers for Chevrolet & GMC trucks but there does not seem to be a list of what each series numbers refers to.

1300 series Canadian Chevrolet trucks were 1/2 ton (3100 series in USA)
9300 series Canadian GMC trucks were 1/2 ton (100 series in USA)

1400 series Canadian Chevrolet trucks were presumably 3/4 ton trucks (3600 series in USA)
9400 series Canadian GMC trucks trucks were presumably 3/4 ton trucks (150 series in USA)

If no one posts information on the 1420 by this evening (or no one corrects mis-information that I have posted above), I'll look in a Canadian Shop/Maintenance Manual and post correct information.

Tim