11mm Carbon or PS Belt?

RCD makes the Carbon and the PS 11mm belt. What is the difference in the application and effects? Which is the best for a 8-71 Methanol chevy?

 

Actually Gates makes the belts for RCD. The purple PS belt has a little bit more elasticity or stretch/give built into it. The blue carbon belt is a lot stiffer and ultimately stronger. The PS purple belt was developed mainly to deal with the 2-step and the rapid oscillation impulse loads which result from that. If you are not 2-stepping or doing anything out of the ordinary, then the blue carbon belt is just fine. The 11mm belts are made exclusively for RCD by Gates. AFAIK you can only get the 11 mm belts from RCD (not 100% sure on that)?? Likewise for the other PS belts. The Blue 8mm and 14mm belts can be sourced through any local industrial supplier as they are a catalogue item.