Still interested in the mopar 8:75 gears The dana is too heavy and there is no way a phord in my mopar will ever happen Ill take all 50 gears sets before a phord diff goes in my mopar ps:we have rules for class 400hp max
Just wanted to offer some insight that is sometimes overlooked when comparing the weight of an 8 3/4" and a Dana 60. The more race oriented modifications are made to both, which usually lighten them, the closer they are in weight. (With 35 splines, axles will be pretty much the same. I don't know if gun drilled 40 spline axles in a Dana 60 would be lighter than 35 spline gun-drilled axles in an 8 3/4)) But going from a Sure-Grip to a spool, you'll shave a lot more weight off of a Dana 60 than an 8 3/4 because the Dana part is bigger and heavier to begin with. Same with lightening the ring gear. The Dana 60 is also more efficient (takes less HP to turn) than other HD rears, including the 8 3/4. (GM 12 bolt is most efficient while Ford 9" is the worst. Not a lot, but differences are there.) This makes up for some, if not most of the weight as there have been several class racers who switched and didn't see any loss in ET once weight was adjusted (Back to minimum class weight.) to make up for the extra Dana 60 weight. It also puts the weight where it will do the most good for traction! Then there is the extra durability that will help preserve a torqueflite trans.
I wish I remembered the exact weight difference when I switched the rear in my Aspen wagon. I'm pretty sure it was less than 60 lbs, but more than 40. But I was confident enough in the benefits vs the small weight increase to do it, even with a low compression 360. I never established a consistent baseline to notice if there were any performance changes due to the switch.
