That's what I had to do recently two local tows. One was a 1955 Clipper and the other a 1989 Chevy Caprice. My friend and I had used his 1995 Ford F-250 Turbodiesel with 5 -speed tranny, many times in previous tows hauling Senior V-8 Packards, G-body and F-body Pontiacs, but U-Haul's computer claimed it was too light! So, we just told the proprietor to input F-350 and everything was fine, including the tow.

Go figure.