I can measure it for you. It’s not on the car anymore, so it’s easy to measure. Actually thinking of selling the spindles with hubs and calipers. If I remember correctly, the rotors are just under 14”.
Weren't those Challenger Scat Pack rear rotors? Those are 13.78" (350mm).
I think some of the SP and Hellcat guys are able to run 17" wheels over those rotors, so they might fit?
I should add that my front brake setup is 13" Cobra rotors and C5 vette calipers and just barely fit my 17" wheels. No way a bigger rotor would fit a 17" wheel with these calipers. So the calipers you run have a huge impact.