The original agreement was for AMC to buy the design, eventually moving manufacturing to the United States and selling the engines back to VW and Audi. American Motors bought a plant specifically to build the engine, but never sold enough to move complete manufacturing. The AMC engines were assembled in the U.S. from major castings supplied by VW, hence the different assembly clearances. As part of the agreement, AMC was not to use the VW or Audi names when referring to the engine. Everyone familiar with the design knew they were virtually identical, and the automotive press commonly referred to them as Audi or VW engines. VW/Audi/Porsche U.S. spec engines produced in mid-1977; earlier models produced -- more than the AMC version.