end of the model year. US "Competition Package" option dropped from production at the end of the model year. 1983 Model designation: 928 S Weight: 1500 kg (3300 lb) Engine displacement: 4.7 L Power: 300 PS (221 kW) / 234 hp (174 kW) (for North America) Changes: North American introduction of "S" model. Standard 928 (4.5 L) model dropped. New style hydraulic motor mounts. Engine shocks deleted at the same time. 4-speed automatic transmission made available for North America. Car body and torque tube changed to accommodate longer gearbox. 1984 Model designation: 928 S (928 S2 in United Kingdom) Weight: 1500 kg (3300 lb) Engine displacement: 4.7 L Valves: Two per cylinder Power: 310 PS (228 kW) / 234 hp (174 kW) for North America. Changes: "S" model renamed "S2" in the UK market. Bosch LH-Jetronic injection and 4-speed automatic transmission made available for worldwide markets (previously available in North America only) Torque tube shortened like on U.S. model in the previous year. Bosch EZF ignition system using dual distributors makes debut. This allows higher 10.4:1 compression and increased torque. Compression change done in the middle of model year once 10.0:1 compression ratio resulting piston stock were used up in production. Bosch ABS brakes optional for the first time in a Porsche. At 146 mph (235 km/h) US model top speed, Porsche boldly claims the 928S to be "the fastest street legal production car sold in the US". Important safety related change to front suspension lower ball joints on all cars in September 1983. 1985 Model designation: 928 S / 928 S2 (UK) Weight: 1500 kg (3300 lb) Engine displacement: 4.7 L (286 cubic inch)/ 5.0 litre (302 cubic inch) for North America. Valves: Two per cylinder (four per cylinder in North America) Power: 310 PS (306 hp, 228 kW) (worldwide) / 292 PS (288 hp, 215 kW) (for North America) / 275 PS (272 hp, 202 kW) (4.7 L) for (Australia) Changes: New 5.0-litre 288 hp 32-valve engine equipped with Bosch LH-Jetronic injection and Bosch EZF ignition made available for the US market. Top speed (for the US model) is now in excess of 250 km/h (155 mph). Special two-valve 4.7 L engine (9.3:1 c/r) option M151 for Australia. Compression change was done with different shape piston tops. Coupled only with automatic transmission. Engine number is same M28/22 as the high-compression 2-valve engines. LH-Jetronic control box design changed in