Originally a Cooper T53 built for the 1961 United States Grand Prix, it was rebuilt for usage in American sports car racing, and featured open-top bodywork.

[2] The wreck was sold by Cunningham to Roger Penske, who replaced the damaged chassis tubing and added full-width enveloping bodywork and named the car the Zerex Special.

[9] Penske then entered the Zerex Special privately at the Grand Prix de Puerto Rico, and this time won the race by three laps from the Cooper Climax of Timmy Mayer.

He started 1963 in the same way that he'd finished the previous year; taking the victory, this time at Marlboro Motor Raceway, beating Bob Holbert's Porsche 718 RSK into second place.

[13] Penske then partnered Hap Sharp in the second round of the United States Road Racing Championship (USRRC), held at Pensacola Airport Course; the car's unbeaten streak finally ended, as an oil pressure issue forced the pair out after 74 laps.

[19] An aborted attempt at entering the Pacific Grand Prix followed,[20] instead, Augie Pabst was the next person to drive the car, retiring from the Nassau Trophy after 26 laps, and being classified in 41st position.

[21] Penske had also driven a Ferrari 250 GTO in the USRRC, and was classified in joint-18th, with six points; level with Chuck Cassel, Charlie Kolb, Don Sesslar, Jerry Titus and Enus Wilson.

[4] The Cooper-Oldsmobile's debut came in the second round of the British Sports Car Championship, held at Oulton Park; however, an oil pressure issue after nine laps forced him to retire.

[29] McLaren returned to the UK, and won the Guards Trophy Brands Hatch; this time, beating fellow countryman Denny Hulme and his Brabham BT8 Climax by 42.4 seconds.