you will need a 2" or possibly a 3" spacer to clear the drums. Find the newer 16" rims that have more than 4 holes if at all possible they have better backspacing...a 2" spacer might be all you need with those.
Other than that your only option is to swap out dually brakes on your SRW axle like I'm going to do. I just lucked into a complete set of brakes. :rockwoot: