Traditionally, the American motorsport authorities have been relatively protective of domestic manufacturers. This was not so much to help them but also to keep the costs down for the competitors. During the 1970s, however, there was virtually no stopping Porsche until the German manufacturer tried to homologate the all-new turbo-engined 934 for the 1976 season. IMSA simply said no to the car fearing it would dominate to an even larger extent as the naturally aspirated cars, requiring all competitors to step up and buy the new Porsche. Realising that the 934 was the way forward, IMSA did allow the 934.5 to be raced during the 1977 season. As the name suggests, it was part 934 and part 935, as it featured a much larger rear wing than before. Eventually Porsche only built ten examples, as the company's customers quickly switched to full 935s. Many of these ten were later also upgraded to 935 specification to prolong their careers. Today, it is a very rare sight but over the years we did manage to capture three genuine examples, which are pictured in this 78-shot gallery.
Another fantastic German racer developed specifically for the American racing scene is the Audi 200 Quattro Trans-Am. Loosely based on the road-going 200 Quattro, this all-conquering machine featured a turbocharged five-cylinder engine and the all-wheel drive system made famous by the Audi rally cars. Run by Bob Tullius' Group 44 team, the cars were raced with great verve by Hurley Haywood, Hans-Joachum Stuck and Walter Rohrl. Even during the 1988 season, the Audis were dialled down with higher minimum weights and tighter restrictors but even in this guise, the 200 Quattro won Trans-Am races. The SCCA eventually decided to ban all-wheel drive altogether for 1988, which meant the 200 Quattro only raced in North America for a single season. Five were built and two survivors are pictured in great detail in this 41-shot gallery.

Enjoy the links:

1988 Audi 200 Quattro Trans-Am - Images, Specifications and Information

1977 Porsche 934 - Images, Specifications and Information