This is powered by a Buick V-6.

https://cars.ksl.com/listing/6938764

“This is a 1951 Willys M-38 Military Jeep that I’ve owned for 50 years. In 1984, I took the whole Jeep apart, painted it and put it back together with a 1981 231ci Buick V-6 certified to have come out of a Buick Regal, wrecked with just 5,000 miles. Engine probably has about 15,000 miles on it now. With a high-rise Edelbrock intake, Holley 390cfm quad and headers, this little buggy has buckets of torque and plenty of power. Brakes are all brand new top to bottom. Ten years ago I had a new top made, complete with canvas side curtains and doors. The seats were reupholstered with black naugahide at that time. The transmission is the stock original Spicer T-90 three speed plus a 25% Full Range overdrive. Transmission was rebuilt 10 years ago. With low range, regular range and overdrive, this Jeep has nine forward speeds and three in reverse. Locking hubs in front.. Always garaged, this Jeep has been my baby all these 50 years, but it’s time to let ‘er go . Feel free to call or e-mail with any questions.”