SAAB Quantum was a series of five privately designed and built automobiles using various Saab components. The earliest used Saab 93 two-stroke engines, transmissions and suspension. The later used Saab 96 drivetrains and suspension parts. All were built in the United States.
The Quantum I was built in 1959, with a chassis computer engineered by Walter Kern at IBM in his spare time. It wore only the most basic bodywork at first. After initial testing and a race or two, it was replaced with moderately more complete bodywork which it still wears to this day. The Quantum II was nearly identical in every way, though built later. Both Quantums I and II were raced in the SCCA H-Modified class. They were pure prototypes and racing cars, never intended for production.
The Quantum III was designed to be a production car and was first presented in 1962. Only a few copies were built. Due to a lack of quality it was turned down by Saab in Sweden and never went into production.