In September 1971, the KGC10 2000 GT-X received a 2.0 L (1,998 cc) L20SU straight-six engine instead of the Prince G-7 engine.
The chassis was already designed to fit a straight six, to avoid the S54 extension problem. 130 PS (96 kW) was available from this new engine. In March 1972 the lineup was expanded to include a four-door GT-X sedan.
In October 1968 the GC10 2000GT's engine horsepower was decreased to 105 hp (78 kW), Nissan introduced an automatic variant in June 1970, as well as a 2-door coupe in October 1970.