I am interested in swapping out my 10 bolt rear in my 88 suburban for a 14 bolt FF. I read the article in the technical section but am a little confused as to what this means. "On newer Chevy's, the brake backing plate (picture H) will have to be changed to a press in style backing plate from a 14-bolt (SF) with 13" brakes." So I will need a SF backing plate? What is the reason for not being able to use the backing plate that is already on the 14 bolt FF?