Ramble Tamble

How did you end up getting the rear axle moved 4" back? did you extend the frame, drive line or brake lines? I am about to start a vary similar project with a 1976 chinook and am looking at what truck I should get to mount the chinook shell to. I have an 1985 extra cab 4x4 but would need to extend the rear axle too and don't know how it would look/ mount up to the extra cab. Any advice or tips would be greatly appreciated. Thanks, yours looks awesome and your videos are great