I'm at a crossroads what I should do on replacing the rear end on my 71' Cuda.

The engine will be 485c.i. stroked 426 Hemi M/T.
Medium cam. Some decent lift nothing too radical.
10.25:1 CR. Gear to be either a 3:54 or 3:73.

My questions are:

Should I get the Dr. Diff leaf spring relocation or stay with the 15" x 7" OEM width I have?

How much does that increase tire width from 15" x 7" tire width if I did?

Is traction significantly improved on a Cuda using his relocation set up?

Any possible way to keep the factory Rallye look with Dr. Diff set up?

These cars are pretty light in the back end and it makes me wonder if it just a "look thing" or a performance upgrade.

What's your recommendations?

Feed back is appreciated. thanks

If you run my 1" offset hanger/shackle kit with relocated perches and the stock width E-body rearend, I recommend 10" wheels with 6" of backspacing.

You can also install a '65-'67 B-body spec rearend with 10" wheels and 5" of backspacing. This will bolt in with no modifications.

You can get new 10" Rallye wheels with your choice of backspacing from Specialty Wheels or Wheel Vintiques.

I like the 28/12/15 Mickey Thompson Sportsman S/R. This 28" tall, 12" wide street radial fills out the rear wheel wells nicely.