When Ford began producing the nearly identical GPW (with Ford embossed on the back panel) in January of 1942, they used the now-standard, less expensive stamped steel slotted jeep grill (photo above, left). The early production Willys MB jeeps, about 25,800 of them, had a grill made of vertical welded slats (called the 'slat grill' type, photo right) and had 'Willys' embossed in the back panel among other small differences. If you are with the jeep, you can see if it has the Ford script F embossed on the rear panel of the body tub or has the F stamped on most bolt heads. There are many other details of the Willys MB or Ford GPW that are different. But, like all other parts, the engine may not be original. The engine has a stamped serial number, starting with MB or GPW which will tell you the origin of the engine.
Unfortunately, the data plate is often missing or has been replaced by an unreliable replica. To discover the origin of a particular jeep, the original dataplate is the best source.
