Whos running over 700whp on an 8.75?

Sounds like you'll be able to sell the 8-3/4 for close to what the Dana 60 will cost you. Easy decision in my book.

Why will you have to move the 4-link mounts?

When I talked to Bill Reilly about doing the 60 swap since its his kit he said the upper mounts on the bar I welded to the car have to be moved further out because of the width of the center section. Idk why I can just use more triangulation. I'm going to call him and ask him that.