Original 1979-80 GMC & Chevrolet Truck Dealer Parts Catalog. This Parts Book covers the Medium Duty School Bus Chassis Models. This is what the Dealer used to order Factory Replacement Parts to Repair your Bus. It has Part Numbers, Group Numbers, Description, Quantity and Application with no Illustrations. It is in good condition with minor wear and soiling [see photos]. It is loose leaf pages with no Binder. Very rare and informative piece that will be a valuable tool for the GMC or Chevy School Bus Owner or Collector.