Small bolt pattern axle to big
I had a wheel adapter fail on me wheel came off and wanting to switch my 8 3/4 small bolt pattern axle shafts to big besides shafts and backing plate. What else would I need and could I reuse the drum brake set up besides the drum
The axle flange offsets are different between the small bolt pattern shafts and the large bolt pattern shafts. What this means is that the flange protrudes farther from the housing with BBP shafts than with the SBP shafts. The drums and backing plates therefore use different offsets to accommodate this. There are many sizes that can be used, from many different donor vehicles including some '73 and later A bodies, B/C/D/F/M/J bodies, some trucks and vans, early 5 lug Dakotas, even some Jeep XJs, among others. But, drums and backing plates MUST be used as a matched set regardless of their source, since so many different sizes and offsets were used.
A body SBP drums (generally) cannot be used because of the difference in offset.
There were (not sure if there still are) axles made with BBP and the A body offset (basically what amounted to redrilled A body axles), but these required the drums to be redrilled to the BBP and sometimes the register hole to be bored out. This means you're married to those drums-any time you need to replace a drum you'll have to get it re-machined, and considering how tough (and expensive) it's getting to find replacements for the A body drums in the first place, I have no idea why you'd want to go that route anyway.
Just get your shafts and use any of the above donor vehicles for the complete (backing plate, drum, hardware) drum setup, that uses cheap and readily available parts.
