The HQ framework led to a new generation of two-door Monaros, and despite the introduction of the similar-sized competitors, the HQ range became the top-selling Holden of all time, with 485,650 units sold in three years; 14,558 units were exported and 72,290  CKD kits were constructed. The HQ series was facelifted in 1974 with the introduction of the HJ, heralding new front-panel styling and a revised rear fascia. This new bodywork was to remain, albeit with minor upgrades, through the HX and HZ series. Detuned engines adhering to government emission standards were brought in with the HX series, whilst the HZ brought considerably improved road handling and comfort with the introduction of radial-tuned suspension. As a result of GM's toying with the Wankel rotary engine, as used by Mazda of Japan, an export agreement was initiated in 1975. This involved Holden exporting with powertrains, HJ, and later, HX series Premiers as the Mazda Roadpacer AP. Mazda then fitted these cars with the 13B rotary engine and three-speed automatic transmission. Production ended in 1977, after just 840 units sold.