The design work for the Su-76 began in November 1942, when the State Defense Committee was ordered to build an infantry support self-propelled gun armed with the ZiS-3 76.2-mm gun and M-30 122-mm howitzer. The T-70 light tank was chosen as the chassis for mounting the ZiS-3 gun. Unfortunately, the T-70 chassis was too short for adequate gun mounting, so the chassis was lengthened by adding one extra road wheel to each side. In a rush to complete the order, a rather unreliable power plant was installed which utilized two GAZ-202 automobile engines set in a "parallel" configuration. As a result, each track had its own powerplant, which made it quite difficult for the driver to control two engines simultaneously. Moreover, the strong vibrations often led to mechanical failure of the engine or the transmission. After 320 vehicles were built, production was halted by the authorities in an attempt to fix these and other problems arising from the Su-76 design. Sold Out!