"The M42 Duster was based on the 76mm gun tank M41, and retained the rear-engine and rear-drive layout. The twin 40mm guns were mounted in an open turret slightly ahead of the hull centerline. The hull featured a large door in the front and two roof hatches ahead of the turret. Early M42s had conical flash hiders on the 40mm guns, but these were replaced by three-pronged flash suppressors later in production. Early Dusters also lacked a muffler for the auxiliary generator engine. One was placed on the front of the right-hand pioneer tool stowage rack, but later in the production run a larger muffler was installed on the rear of the tool rack. The hull roof between the driver and vehicle commander was formed by front- and rear-opening doors on early vehicles, but these were later eliminated. "

The fuel-injected AOSI-895-5 engine of the 76mm gun tanks M41A2 and M41A3 was installed in the M42 when the kits became available, changing the designation to M42A1. The fuel injection system increased the M42A1's road range to around 120mi (190km).