If you look in the archives you'll see a couple of magazine articles that I wrote on Tim's Valiant. We put a 13 inch Baer 6P kit on his Valiant and it works fine. Tim's car is road raced and has 150+ mph capability so it is very fast for a vintage Mopar. We could've gone 14 inch or 15 inch on the rotor size but there wasn't any reason to do so. The 13 inch rotors do the job from 150 so why go bigger. A 14 inch rotor does give you a little more leverage and a little more surface area and perhaps some additional head sink. I doubt that very many guys on here have a car that is fast enough to require a 14 inch rotor but nothing wrong with putting them on a car if you have the cash and don't mind spending it.
I'm probably the only one on this board who has not only had both the 13 and 14" systems, but has had them on the track as well. My Dart is probably 600lbs heavier than Tim's Valiant which plays a huge roll in brake performance.
Another thing to consider is feel and balance. This is almost more important than the brakes themselves. Most on the board don't understand this factor.
Even though the 13" system was adequate, the 14" is far superior in braking and confidence. I had the complete system working for years and changed to the 14s by themselves. I also run an expensive set of Carbotech pads.
Bottom line, if you can afford it, brakes are worth it!
