new overhead camshaft (OHC) 6-cylinder engine in the Tempest. The 1962 Jeep Tornado engine was the first post-World War II U.S.-designed mass-produced OHC engine while the Pontiac OHC I6 was available in popular-priced domestic cars. In an industry first, plastic grilles were used on several models. The 1967 model year saw the introduction of the Pontiac Firebird pony car, a variant of the Chevrolet Camaro. Intermediate-sized cars (Tempest, LeMans, GTO) were mildly face-lifted, but all full-size cars and GTO lost their Tri-Power engine option, though they did get a larger V8 that replaced the previous 389. Full-sized cars got a major facelift with rounder wasp-waisted body lines, a name change for the mid-line series from Star Chief to Executive as well as a one-year-only Grand Prix convertible. 1968 introduced the Endura 'rubber' front bumper on the GTO, the precursor to modern cars' integrated bumpers, and the first of a series of "Ram Air" engines, which featured the induction of cold air to the carburetor for more power. The Tri carburetor deletion came from the 14th floor of GM banning multiple carburetions and was headed by GM president Ed Cole. The Ram Air V option was not popular. Full-sized cars and intermediates reverted from vertical to horizontal headlights while the 2+2 was dropped from the lineup. For 1969, Pontiac moved the Grand Prix from the full-sized lineup into a G-body model of its own based on the A-body intermediate four-door modified from to wheelbase chassis, but with different styling and long hood/short deck proportions to compete in the intermediate-sized personal luxury car segment. Pete Estes, who like Knudsen had moved to be general manager of Chevrolet in 1966, and DeLorean, general manager of the Pontiac division, needed a car to take the place of the sagging sales of the full-size Grand Prix, but the development cost of the car was too much of burden for Pontiac division alone, so Delorean went to his old boss at Chevrolet to gather support for the development cost of the new "G" body Grand Prix. Estes agreed to share in the cost and allow Pontiac to have a one-year exclusivity on this new car; the next year Chevy would follow with its version which was called Chevrolet Monte Carlo. The new Grand Prix was such a sales success in 1969 as dealers moved 112,000 units - more than four times the number of Grand Prixs