https://www.stovebolt.com/ubbthread...ear-axle-swap-gm-14-bolt.html#Post723208If you have a dual wheel truck you need the cab and chassis 14 bolt just as it comes (except for spring pad location) with the drums it comes with that fit in dual wheels.
If you want to run single wheels then you can use shallower drums with same brake area, same backing plate and shoes, but new mounting flange on axle for the new backing plate location.
The advantage of the shallower drums is they look better from the back end of a single wheel truck, and they allow plenty of room between backing plate and spring pack for the u-bolts and access to brake bleeder screw.
The 14 bolt C&C axle with the drums they come with leave very little room between spring pack and backing plate, but should be just enough room to make it work. Reason for not much room is the 14 bolt comes from a truck with nominal 34" width over rear frame, and the AD truck has 36" outside the rear frame.
