A body Dana 60
I was watching a show one day that actually went into this topic. They took an a body with an 8 3/4 3:91 rear and ran it down the the track 3 times then replaced the 8 3/4 with a Dana 60 4:10 rear and ran it down the track 3 times and took the best time of each and compaired them, they found that there wasn't really enough of a difference to state which was better. They figured that they kinda cancelled eachother out sortta speek. Basically the 8 3/4 was lighter i.e fast enough to keep up with the Dana 60's big gears and the Dana 60's big gears sent the car down the track fast enough to keep up with the lighter 8 3/4.
I hope that helped, sorry i can't remember the shows name but there are two hosts an older guy balding who likes mopars and never gets to drive the cars and a younger guy drives the cars and is kindda anoying,