8 inch backing plates

will the backing plate from an 8 inch rear swap over to a 9 inch rear

 

If it is a big bearing 8", it is a direct swap for a small bearing 9".
Dave

 

plates

as long as the bolt pattern is the same and the bearing opening is the same for the housing end. Other wise you have to either get new plates or change the housing ends, There is some small bearing 9" that match the 8" so you'll just have to check. If you have the old 9" plates, just compare them.

 

There is only one small bearing 9" and it is same as big bearing 8".
The other 2 possible are Torino 9" and Big 9".
The 8" will only be small bearing if it is 4 lug axles.
5 lug 8" will be big bearing 8".