the engine extended back into the vehicle's passenger compartment, and was covered by a removable cowling. the vehicle thus had a very short bonnet, giving it its distinctive look. this configuration meant that the driver and passenger were travelling with their feet alongside the engine, but allowed a good proportion of the vehicle's overall length to be used for its payload. access to the engine for routine checks was via the tiny bonnet flap, or through the interior cowl. for major overhaul of the engine, the front panel containing the headlights and grille, and the chassis front crossmember had to be completely removed. a popular aftermarket conversion of the time was the use of the perkins 4/99 diesel engine. this was low on power (40 bhp) but was capable of superior fuel economy.