Um... incorrect. My '72 Swinger has factory KH brakes and the original 14" steel wheels, and my '67 Dart GT has retrofitted KH brakes and uses the same stock 14" wheels. Guess you're referring to the 13" steelies not fitting with KH disks?
This is what we have been told - perhaps the rims you used orig. are the 5-1/2" wide version? (Hollander 717) as opposed to the 4-1/2" version (Hollander 716)?
and to answer an earlier query, GM used this caliper from mid 80's to mid 90's on a couple million cars - I do not see this drying up any time soon... If we found an affordable source (NAPA, Autozone) for the OEM calipers and any source for the rotors we would have doped out a way to use them instead...
