My 10" drum backing plates off a 7&1/4 bolted right up to an 8&3/4" no problem. It looks like the 8&1/4 is the same pattern and spacing though it only uses 4 bolts instead of 5.
If so this kit may be able to be used on an 8&1/4.
Anybody have a set of 7&1/4 BBP or 8&3/4 backing plates they can test fit on an 8&1/4 ?
I am prob gonna go with an 8&1/4 for now as i dont have all the pieces for an 8&3/4. But if its something thats swappable.
