I just put a set on my new Challenger. They fit great and Dales was great to work with. No complantes on the new cars. I cannot say about the old cars but I don't see why that would make a differance. The quality of the louvers is outstanding. Just my .02

'09 Challenger R/T '70 Challenger T/A 340 6Pak and Auto I was born with nothing and I still have most of it left!