Lifetime Premium Member
Join Date: Dec 2016
Location: Jefferson County, WA
Re: 12 bolt from hades
The factory shock and control arm mounting bracket is actually a single bracket that wraps around the axle tube, while combining both functions. The coil spring mount is separate. I recently purchased a rather rare 12-bolt housing where some genius had very crudely attempted to relocate the shock/control arm mounts. Given I wanted to retain a factory configuration, I had a professional welder friend remove the butchered shock/control arm brackets from the 12 bolt I had purchased, then cut a serviceable pair of shock/control arm brackets from a spare 10-bolt rear axle I had laying around, and using another complete rear end as a measuring template, weld the 10 bolt brackets to the 12 bolt I had purchased.
The only problem with using aftermarket brackets is that the shock and control arm brackets are 2 separate pieces, not a single piece as the GM brackets are designed to be. But if not concerned with originality, I would use the aftermarket brackets.
But before you cut anything, on second look, I would compare this rear axle with a known factory set up, as the shock/control arm brackets look to be unmolested and in the right place to me. I could be wrong, but I do not think so. You will most definitely need new spring mounts. Those are pretty comical. Use the late year '67 and newer "top hat" design, which is superior to the early version.