[Stuart]

All Pontiac models that year would have come with the same brakes as standard equipment. There may have been a heavy duty option for heavy duty chassis cars (like police cars, taxis or ambulances); the option would have been for finned brake drums and/or possibly metallic brake shoes, but the dimensions of the shoes would have been the same.

You can look at a parts catalog on the Pontiac Safari website: http://www.pontiacsafari.com/MPC/index.htm