11" Backing plates rubbing

When I had the big bars in the car it stopped fine because the front didn't drop in hard braking but with the 6 cyl bars the front would dive taking weight off of the rear so I had to adjust the pressure to the rear till I found the sweet spot then it would haul down hard. Just like the car would spin the tires easy 1st 2nd 3rd gear with no problem with the big bars and HD shocks, then changing to 6cyl bars and 90-10 shocks it would only spin about 1 ft in 2nd gear and smash you back in the seat because the front would lift and put more weight on the rear tires.