ENV) were fitted to improve vehicle stability, as was a front anti-roll bar and revised rear springs which were mounted above the axle rather than below it. In the process the wheelbase was increased to . Production ended in 1974 when Land-Rover rationalised its vehicle range. Many IIB components were also used on the "1 Ton" 109 in vehicle. Series III The series III had the same body and engine options as the preceding IIa, including station wagons and the One-Ton versions. Little changed cosmetically from the IIA to the series III. The series III is the most common series vehicle, with 440,000 of the type built from 1971 to 1985. The headlights were moved to the wings on late production IIA models from 1968/9 onward (ostensibly to comply with Australian, American and Dutch lighting regulations) and remained in this position for the series III. The traditional metal grille, featured on the series I, II and IIA, was replaced with a plastic one for the series-III model. The 2.25-litre engine had its compression raised from 7:1 to 8:1, increasing the power slightly (the high compression engine had been an optional fit on the IIa model for several years). During the series-III production run from 1971 until 1985, the 1,000,000th Land Rover rolled off the production line in 1976. The series III saw many changes in the later part of its life as Land Rover updated the design to meet increased competition. This was the first model to feature synchromesh on all four gears, although some late H-suffix SIIA models (mainly the more expensive Station Wagons) had used the all-synchro box. In keeping with early 1970s trends in automotive interior design, both in safety and use of more advanced materials, the simple metal dashboard of earlier models was redesigned to accept a new moulded plastic dash. The instrument cluster, which was previously centrally located, was moved to the driver's side. Long-wheelbase series-III vehicles had the Salisbury rear axle (the differential housing and axle case are one piece) as standard, although some late SIIA vehicles had them too. North American sales from the factory ceased in 1974. In 1980, the 2.25-litre petrol and diesel engines received five main bearing crankshafts to increase rigidity and the transmission, and axles and wheel hubs were strengthened. This was the culmination of a series of updates to the transmission that had been made since the 1960s