Armond, the Model A roadster that we took out to Bonneville for the last 9 years started out with a Latner quick change. It was basically a '39 Ford pickup truck rearend with the rear section cut out and a boxed housing fabricated to hold the quick change gears in. These were built up here in Ontario in the early 50's. The owner took the quick change out 3 years ago and put in a GM Metric 7.5" 10 bolt rearend. After much research, he discovered that this rearend takes the lest amount of HP to drive it. If I remember correctly, the 9" Ford takes about 15%, the GM 12 bolt was about 11% and this one was about 9%. He did make up new tubes with a full floating spindle on the end so you don't loose a wheel if the axle happens to break. This combination has worked great for him. Just have to figure your gear ratio out ahead of time. Have to remember, you are not running on asphalt when you leave the line and with the Model A, he only has 3rd and 4th gear in the Muncie and we push start it. As for torque, it is running a 436 cubic inch Hilborn Injected Nailhead Buick (the original dump truck motor) so I don't think the Jimmy would be any harder on the rearend than the Nailhead was. PM me if you want more info.
