I got what looks to me as a not normal backing plate on my 12 bolt... The Chevy BOP wheel cylinder does not fit the plate.... The plate part# best I can read is delco 5465513-R. The wheel cylinder comes back as a dodge part. 29477-c which was on the backing plate.. here is a link to a set of plates for a 12bolt https://www.ss396.com/chevelle/FBP-...mHffyGpR4SlOBmGt1IAqFQBdTDaIVavxoCWgUQAvD_BwE pics of what I got..... and a pic of a chevy cylinder... Chevy BOP cylinder..
