To build the experimental prototype 3-5-5I (“izmenonnyy“ – “changed”), engineers took the second prototype of the 3-5-5 model, finished in cherry red, and reworked it: the front section of the body was fitted with longitudinal members designed for improved energy absorption, the rear axle was widened, the wheels were enlarged, and tires of size 6.45-14 were installed.
The car was completed in December 1973. It underwent testing on the cobblestone road at the NAMI proving ground, where it was involved in a serious accident.