that when the car would be ordered or recognized as a Centurion it would be branded as a 4P Series as the first two letters of the Vehicle Identification Number. Interior trim was upgraded from LeSabres with a notchback bench seat including center armrest standard equipment along with more luxurious cloth-and-vinyl or all-vinyl upholstery. In March 1971, the three-speed Turbo Hydra-matic transmission became standard on all Centurions as well as the lower-priced LeSabres. Variable-ratio power steering and power front disc brakes were standard equipment during the entire model year. Total sales were 29,398, exceeding the Wildcat by nearly 25%. 1972 The 1972 Centurion featured minor appearance changes including a revised vertical bar grille and taillight lenses. Under the hood, the standard and only available 455 cubic-inch V8 was rated at 250 net horsepower, which represented an "on-paper" decrease from the 315 gross horsepower rating in 1971. This was due to an industry-wide change in horsepower measurements from the gross method by a dynamometer outside a vehicle with no accessories installed to a SAE net method in which horsepower was measured as installed in a vehicle with accessories and emission controls hooked up. Turbo Hydra-matic transmission, variable ratio power steering and power front disc brakes were again standard equipment. Sales climbed over 20%, to 36,165 for the model year. 1973 The 1973 Centurion featured a larger front bumper and new vertical grille shared with LeSabre models along with revised taillights. The two-door hardtop coupe no longer included a standard vinyl roof and the distinctive formal rear window was replaced by a backlight shared with LeSabre coupes. Under the hood, the standard engine was downgraded to a four-barrel 350 V8 rated at 175 net horsepower. The 250-horsepower 455 four-barrel was now optional. With the LeSabre convertible temporarily dropped after 1972 and the intermediate-sized Buick lineup (renamed from Skylark to Century for 1973) losing its droptop permanently after the 1972 model year, the Centurion was Buick's only convertible offering in 1973. This would also be the final year for the Centurion series, which was replaced for 1974 by the new LeSabre Luxus, which included the convertible reinstated to that line for another two model years. GM would not see another Buick convertible until the Buick Riviera in 1982. Total Centurion production was 110,539 units, including 10,296 convertibles. With only three years of production, the Centurion had one of the shortest model runs in