As for the hours spent on the wheel tire combo, who knows? I have a 9" rearend and a 4" back set wheel. It seems that the 4 to 4 1/2" back set wheel workes the best however I have used a mustang wheel with a 5 1/2 back set and a 1/4 spacer and it works but depending on the tire size the tire side wall may rub the Ebrake cable.