but this speculation remained uncredible as Porsche denied the possibility of any such model reaching production stage. Evolution The evolution of the 928 during its 18 years of production was quite subtle. The tables below show the major differences, which were made to the nose, tail, interior, engine, and wheels. 1978 Model designation: 928 Engine displacement: Valves: 16 Fuel feed: Bosch K-Jetronic fuel injection Max. Power (DIN): / (North America) Max. Torque: 1979 Model designation: 928 Power: 240 PS (177 kW) / 219 hp (163 kW) (North America) Changes: Battery box integrated as part of the body, was previously mounted to gearbox. Gearbox shocks deleted. 1980 Model designation: 928 / 928 S (only 928 in North America) Engine displacement: 4.5 L / 4.7 L (S model only) Valves: 16 Power: 240 PS (177 kW) (4.5) / 300 PS (221 kW) (4.7 S) / 229 HP (167 kW) for North America only. Changes: Higher 10.0:1 compression ratio engine (except North America) 4.5 L model. Same power, i.e. 240 PS (177 kW) but more torque, 380 Nm instead of 350 Nm. Bosch L-Jetronic injection in North America. Addition of "S" model, shown at Frankfurt in September 1979. The 928 S was not available in North America until 1983. Front & rear spoilers. Larger brakes. Manual gearbox changed during model year requiring shorter torque tube and different rear subframe. "S" brakes installed during model year except North America. 1981 Model designation: 928 / 928 S (928 in North America) Engine displacement: 4.5 L / 4.7 L (S model only) Valves: 16 Power: 240 PS (177 kW) (4.5) / 300 PS (221 kW) (4.7 S) / 229 HP (167 kW) for North America only. Changes: "Competition Package" option available to US market. 1982 Model designation: 928 / 928 S (928 in North America) Engine displacement: 4.5 L / 4.7 L (S model only) Valves: 16 Power: 240 PS (177 kW) (4.5) / 300 PS (221 kW) (4.7 S) / 229 HP (167 kW) for North America only. Changes: Vibration damper added to torque tube between 2nd and 3rd support bearing on manual gearbox cars and behind 2nd bearing on automatic gearbox cars. Reverse gear lock added to manual gearbox. 141 "50th Jubilee" 928 S produced for worldwide markets except North America. "S" brakes used in US models. 202 "Weissach Edition" model produced for the US market. 4.5 L model dropped from production at the