[Rory McNeil]

Gotta agree with Mr. Hill. I think a lot of the reputation of a Dana 60 comes from when a stock Sure Grip limited slip unit is used. (about 40 lbs). On my bracket Fairmont, the first diff was a Ford 9", using a shortened OE Ford housing, a factory Nodular iron case, 33 spline spool and axles. It worked fine with the automatic, but when I switched to the Jerico 4 speed, I figured therearend would be marginal as it was. While pricing out a new braced housing, aftermarket case , bigger axles and spool, a buddy suggested selling the 9" and building a Dana 60. Turned out to be a good move.
My Dana used a 3/4 ton Ford truck housing which has thick axle tubes, 35 spline Strange spool and axles, and a T/A girdle cover. Using the same brakes as the 9" had, the finished Dana weighed a mere 6 pounds more than my 9" did. But keep in mind, if we would have added a brace to my existing 9" housing, installed 35 spline spool & axles, and an iron Strange case, I doubt the 9" would have been any lighter at all. Yes, I am aware that aluminum 9" cases are available, which would shed some weight, but then a car Dana with thinner tubes could have been used as well. I have been using that Dana behind the 4 speed for 17 years now, never dropping the clutch below 6000 RPM, and the only time the cover has been off was for ratio changes, and all 3 gear sets still look like new. I only see 2 downsides to the Dana, selection of ratios not as wide as a 9", most ratio changes will change the trap RPM by 250-300 RPM, a 9" has much more variety and will allow for much closer RPM change. Also setting up a 9" on the bench is easier than doing it under the car, or removing the whole rearend. If you have the money and space, you can have multiple 9" chucks set up ready to go. My Dana cost a fair bit less than my 9" did, in fact, selling my old 9" almost covered the cost of the new Dana.
I know several MoPar racers that spent a lot of money, and broke a lot of pieces with their 8 3/4s, most went the Dana route and have been really happy with the swap. You can always find somebody to buy your good used 8 3/4 stuff, but once its broken, its just scrap metal.