I'm going have a dana 60 installed in a 67 satellite that has been mini-tubbed. I was told that in order to narrow the dana correctly, I should buy the wheels and tires and mock it up by putting them under the car and measuring. I like prostar 96's 15x10" wide but I'm not sure about backspacing. I can choose 5.5, 6.5 or 7.5. The engine is done,I have about 650-700 Hp and I want the car to be streetable. Should I pick the 6.5" backspace? I think maybe the ET street would be a good tire but I don't really know. I want to drive to the track, shows, etc. I appreciate any help, this car has been in my barn for at least twenty years waiting for me to put it on the road.

Yep you need to pick your rims. Measure the clearance between the fender lip and the tub. Measure you backspace side to side to get the width axle you need.

When I did mine last year I bought 12" rims with a 7.5 backspace and left the rear end stock! but my 68 has more room on the wheel wells.

First measure from the front of the brake drum wheel mounting face back and forward to see how much room you have. the look up the tire you want to use and look for the center section with.

Lets say it 13.5" so on a 10" rim it will stick out 1.75" either side of the rim and you want at least 3/4" clearance outside so you need 15" min to fit said tire in! Then so you have to allow 2.5" outside the rim front and back.
so say you have a 10" rim and get a 6.5" backspace from the face of the brake drum you would need 9" back to the inner wheel tube and 6" out to the quarter panel wheel opening. Kinda not shortening rear end set up!

So if you are going to shorten the rear 4" then you would want 2.5" backspacing and have 5" back to the inner tube and 10" out to the wheel well opening.

The wheel with the least backspace will be the lightest. Not the wheel itself, but the whole tire/wheel/Dana combo. It will also make it easier to remove the wheels from the car.

Hey thanks for the advice-it's needed and appreciated. I guess since I am getting a custom Dana 60 built, I have some flexibility. I'll have to measure now to determine what size tire/wheel I can get under the car. There is an 8 3/4 under there now to measure off of. Also, I need to pick a type of tire to buy rims. I want to build this car mainly for the road, not track, so maybe I need radials for that. Thanks again, I will need lots of help with this project, I need to get this done before I marry my girlfriend and she starts looking at my checkbook. (Offshore account soon?) I will measure tomorrow.