917.028 was Porsche's first Can-Am car for the 1969 season, basically a 908 type body on a 917K chassis. It led directly to the 917/10 and 917/30 championship cars of 1972 and 1973.
Porsche's decision to enter Canadian-American Challenge Cup Series was made mid-season 1969. Porsche would provide the car, driver Jo Siffers, full support crew, and the new Porsche & Audi Division of Volkswagen of America would sponsor the entry. Work began after LeMans in June and the 917 PA (Porsche/Audi) arrived in the States in August.
A makeshift solution, the PA was 917 short of its coupe top and fitted with a body inspired by the 908/2 Flounder prototype. The 100 or so pounds saved were offset by a 56 gallons of fuel required to run these sprint races nonstop.
This 1969 Porsche 917 PA has Serial Number 917 028 and is powered by a 4,494cc, flat-twelve, air-cooled engine, mounted midship, with twin overhead camshafts, fuel injection and develops 580 horsepower at 8,400 rpm. It rests on a 90.6 inch wheelbase and weighs 1,710 pounds. At the starting line at Mid-Ohio 917 PA gave a way three liters, 200 pounds and 250 horsepower to the Chevy-powered Team McLarens.
Five races had already been missed. In the six that remained, thanks to its endurance racing reliability, the 917 PA finished in all but one, took second once - and placed fourth overall in the Can-Am championship. Naturally, Porsche was encouraged and went on to launch a full Can-Am assault with the 917/10 and 10 Turbo taking the Can-Am laurels away from McLaren.