Putting a late model 8 1/4 Jeep rear end in a 66 Dart

If you are going to put money into an axle, and it is NOT an "original type" Mopar such as 8 1/4--8 3/4 etc, don't discount Ford 9" --I am partial to 3rd member axles as they are much easier to swap ratios

And yeah.........You'll have to narrow them unless you find the "Gold mine" of something like a Mustang axle