I too have the A153-1 kit on my '71 Dart GT and I'm also wondering about replacement rotors. I can't find any part number/cross reference information about them either.

Since this is a kit, would it be safe to assume the rotors are off the shelf from X vehicle (versus manufactured specifically for this kit)? And, because the kit offers the use of either the small bolt pattern or the large bolt pattern wheels are there any production vehicles that have the dual bolt pattern? Or, would SSBC would have drilled the rotors for the "other" bolt pattern?