through 1978 in the United States, the RX-3 version was extremely successful. It originally used a 10A rotary engine like the Mazda Familia Rotary Coupe/Mazda R100, but US cars shared the larger 12A engine from the RX-2. Performance-wise the 10A RX-3 was not able to match the RX-2 with 12A. With a weight-to-power ratio of 10.9 kg per kW compared to the RX-2's 9.9 kg per kW, the RX-3 was slower. The 12A RX-3 wasn't able to match the RX-2 with 12A either, despite its lighter weight. The smaller engined version has the internal model code S102A, while the larger one is known as the S124A. In Japan, the installation of a rotary engine gave Japanese buyers a financial advantage when it came time to pay the annual road tax in that they bought a car that was more powerful than a traditional inline engine, but without having the penalty for having an engine in the higher 1.5 litre tax bracket. Series I S102A & S124A (1971–1973) The first Mazda Savanna went on sale in September 1971 and remained in production until 1977. It was sold as the Mazda RX-3 internationally when installed with the rotary engine and was otherwise largely identical to the inline-four-equipped Mazda Grand Familia. Externally the Savanna and export RX-3 was differentiated from its piston engines sibling by a nose panel with dual round headlights and a more prominent and pointed honeycomb grille, and round tail lights on the rear of sedans and coupés. A station wagon version, the RX-3 Sports Wagon, was sold for just one year in the U.S., from 1972 to 1973, when it was replaced by the Luce/RX-4 wagon. However the "Savanna Sports Wagon" remained in production in Japan right through until the end of Savanna production in 1977. Initially in all markets except North America all cars were designated S102A and came with the 982 cc (2x491 cc) 10A. S124A cars introduced later on came with the 1146 cc (2x573 cc) 12A. While the larger S124A eventually replaced the S102A in most markets, the S102A remained on sale alongside the S124A in Japan through to early 1974 with all the Series II updates. The Series I S102A remained on sale in some markets even longer, being available in the United Kingdom until the 1975 model year at least, though this was most likely as a result of stocks of earlier production