65 Mustang-Ridetech 4 link with DSE mini tubs

[dontlifttoshift]

The inside of the frame rails, where the RideTech crossmember bolts in, doesn't move. You are narrowing the frame rails themselves, as in they were 2" wide before and now they are 1" wide.

You may be wasting your time narrowing the rails with that 4link. The lower bar will be the limiting factor in getting more tire under the car, not the wheel tub. You could leave the frame rails alone and a 295 might clear the lower bar with only a 2" deeper tub instead of the full 3".