Ford 9 Inch Bolt-On Rear Disc Brake Kit w/ E brake 
Drilled and Slotted Rotor
 
Fits both 5 on 4-1/2" and 5 on 4-3/4" bolt circles
For Ford passenger car axles ONLY 
Fits axle with maximum flange diameter of 6-1/4" O.D.
For 15" and larger wheel applications ONLY
NOTE: This bolt on brake kit is designed to be used on 8" and 9" housings using 3/8" retaining bolts. 
If you want to use it on a 9" housing with 1/2" bolts, you will need to use the 3/8" hardware to do so. Fits "old" and "new" style big bearing (3.150" bearing O.D.) 
Ford housings and with axle offsets of a minimum 2-3/8" to 2-1/2".