the larger engine placed it in a considerably higher tax category. The Japanese-spec 2.4-litre engine produces a claimed JIS at 5600 rpm but was discontinued in 1973 as sales had dropped considerably as a result of the fuel crisis, and so until the August 1978 introduction of the Fairlady 280Z only two-liter Fairladys were available. When export models changed over to the larger 2.6-liter 260Z in 1974, only 2-liter models remained available to Japanese buyers. A Fairlady 260Z had been planned for release, but the impact of the oil crisis stopped the model, although the 260Z was available in Okinawa (which drove on the right side of the road until 1978). The Fairlady Z received all the changes as applied to the export models, including the addition of a long-wheelbase 2+2 model. Introduced in January 1974, this received the GS30 chassis code. In 1975 the L20 engine gained fuel injection to meet new emissions standards (A-S30, A-GS30) and once again provided JIS. At the end of July 1976 the car received the NAPS system, including an EGR system, to meet the stricter yet emissions standards in effect for this year, bringing with it a change in model codes to S31 (C-S31/C-GS31). At the same time, the more luxurious Fairlady Z-T model was introduced - this was strictly an equipment level and did not include a T-bar roof, which was first seen on the succeeding generation Fairlady. Fairlady ZG The Japan-only HS30-H Nissan Fairlady 240ZG was released in Japan in October 1971 to homologate the 240Z for Group 4 racing. Differences between the Fairlady ZG and an export-market Datsun 240Z include an extended fiberglass "aero-dyna" nose, wider over-fenders riveted to the body, a rear spoiler, acrylic glass headlight covers and fender-mounted rear-view mirrors. The ZG's better aerodynamics allowed it to reach a top speed of , five more than the regular Fairlady 240Z (automatics' top speeds were another 5 km/h lower). The Fairlady ZG was available in three colours: Grand Prix Red, Grand Prix White, and Grand Prix Maroon. The "G" in Fairlady ZG stands for "Grande." Although the ZG was not sold in the US and was never sold outside Japan, in order for it to be eligible for competition in the US, Nissan sold the nose kit as a dealer's option which is known as the "G-nose". With the nose added, these 240Zs are often referred to as 240ZGs