5. Volvo TP21
Although Volvo is not famous for military production, in 1953 they introduced the TP21. It is an off-road army vehicle powered by a 3.6-liter, 90 HP strong straight-six engine. Volvo produced around 7,000 of them until 1958. Some were pure military models in a drab green color, while some were civilian or ambulance versions they intended for use on rough terrain.