Currently running a stock width 8 3/4 in my Dart. The car is mini tubbed and has the 3" inboard kit installed.
If I go with the Dana will I have to shorten my drive shaft? Yes about 1.25" shorter
I had one made with the larger U-joints when I switched from the 7 1/4 rear to the 8 3/4 rear.
Will the Dana fit with the stock gas tank? Yes, as long as stock location and you don't use one of the ultimate aluminum covers
Are the U bolts the same as well has the shock plates from the 8 3/4? Yes, as long as the axle tubes are 3". You can get some U bolt from Dr Diff that are tight radius for the 3 1/8" tubes.
The 8 3/4 has held up great with no problems with my other 440's I've had in the past, I'm just leary with the 512" in there now thinking that my rear is possibly the weak link now. Also like the awe factor of a Dana sitting outback makes people wonder...
