Got the shims. Thanks so much. However, I discovered the kit, bought second hand, has the wrong caliper brackets. None of the disc brake bracket bolt holes line up with the axle flange and they clearly are for a different rear end, perhaps a big car or a blue oval product. I'm getting a set of caliper brackets from Mike Garrison any way because I wasn't planning to use these. It wouldn't be custom if you could just throw it on. LOL! Once I get it on, I'll make a list of parts and maybe get Mike to make a new bracket for this caliper that will clear Buick disc brake wheels.
Looks like a full-size car pattern,or something with a symmetrical pattern. The A-body,F-body have an irregular pattern. The two top holes are farther apart.
Yep, it was pretty obvious when I put the shim up next to it. I hadn't paid it much attention until I had something to compare it with. I'm just glad I found it before I started taking it apart to mock it up.