I have a 73 newport c-body set of axles in my 72 4X4 8 3/4 housing to get the 5 on 4.5 wbp

same size housing and axles truck/later c-body

spring perches are diff on them though

I also have a 67 polara 8 3/4 that has 30 axles and 56' housing/46" spring perch centers..its a c-body also I am told

if you look in the archives..FYI one of the charts has wrong measurments