"pontoons". The 1957 models featured enlarged front wheel well openings, to almost "normal" size. The wheels were now 14-inch with standard 8.00 x 14 tires. The standard engine for the 1957 Ambassador was AMC's own V8, a modern overhead valve design displacing . It featured a forged steel crankshaft, a 4-barrel carburetor, and dual exhausts. The new engine was rated at and of torque. Available were a 3-speed manual transmission, an automatic overdrive unit, or Packard's Ultramatic automatic transmission. The Custom models standard features included power brakes, individually adjustable reclining front seats, rear seat center armrest, hood ornament, and many more. Special leather seating surfaces were optional as well as a continental tire kit. After production of under 3,600 big Nash cars, the final Nash Ambassador rolled off the Kenosha, Wisconsin production line in the summer of 1957. Nevertheless, the Ambassador - as a top-of-the-line model name - would continue to be marketed, under Rambler and AMC brands, through 1974. Racing Endurance Eight Nash Ambassadors were entered in the 1950 Carrera Panamericana, a endurance race run over five days across Mexico. 47 of the 126 cars that started this "contest of heroic proportions and vast distances" were classified as finishers. Three Ambassadors finished all nine stages, but the highest-placed car was disqualified. The 1950 Ambassador driven by Roy Pat Conner was in sixth place after the eighth stage, 33 minutes behind the leader, when Connor became too ill to continue. Curtis Turner, who shared another 1950 Ambassador with Bill France, Sr., purchased Conner's car for its superior race position, replacing Conner at the wheel and leaving France to continue in their original car without him. On the final stage Piero Taruffi, arguably the most experienced road racer in the field, had moved his Alfa Romeo 6C up to the fourth position when Turner passed him in the mountains by bumping the Italian "Southern-style" until he yielded. Taruffi repassed the Nash when it was temporarily halted by a flat tire. At the finish, Taruffi was in Turner's sights but Turner ended ahead in elapsed time, beating Taruffi by 3.5 minutes. This put Turner in third place overall, behind a Cadillac 62. He was disqualified when a quick review by the race officials showed that the rules specifically prohibited changing a car's crew. Bill France eventually crashed out of the race but the damaged car was driven back to the United States,