Looks to have a WWII head. The rear cargo area has been diamond plated.

https://medford.craigslist.org/cto/d/1951-willys-cj3a-jeep/6693552515.html

“1951 Willys CJ3A Jeep, L-134 engine, T90 manual 3 speed transmission, Dana 18 transfer case, Dana 25 front differential, Dana 44 rear differential. Engine runs very well but has 50 psi compression (a bit weak). Shifts great, drives good. “Mile Marker” MM front locking hubs. Solid body and frame, no rust. New carter carburetor, new gas tank, like new soft top, great tires. Basically a real nice rig.”