if it's a 1" wide rotor, late B? 11.75" rotors became standard on the late B/R's ~'76 or so.

if it's a 1.25" wide rotor, I'd wager truck or C body

1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)