The Acremaster 421 is a four-wheel drive (4WD) tractor from the 400 Series produced by Acremaster between 1982 and 1984. It features a powerful Mercedes-Benz OM421 11.0L 6-cylinder liquid-cooled V6 diesel engine delivering 210 hp (156.6 kW) at 2350 RPM. The tractor is equipped with a 9-speed gear transmission with 9 forward and 3 reverse gears. It has a large fuel tank capacity of 268.4 gallons (1015.9 liters). The 421 weighs 20,723 lbs (9,399 kg) and rides on 18.4x34 tires front and rear. It includes articulated power steering and a standard cab with air-conditioning. Built in Merredin, Australia, the 421 is part of the 400 Series and related to the Acremaster 422A model.