When I was doing tech-school '83-'85, My main car pool local's folks had a '77 Chrysler TANK w/a 400 lean-burn, We rode that thing a number of times to school. Ran perfectly, and got~17-18mpg, no balls..but..
Lots of reasons for having no balls but usually because of the rear gear. Think of this, a 2.24 rear gear was available in the 8 1/4 rear that came out in 72.
2.24, 2.45, 2.72 and up. Yep, those low ratios and the big car wouldn't fall out of a tree.