[VintageUpgrades]

Half of the cars that leave our shop have belt driven vacuum pumps installed on them (SPF or otherwise). As far as Roush engines go, we use mostly the SR versions with the TW cam. They produce more vacuum than the R versions. I have not had a problem with the rear calipers in any of their incarnations. The driveshaft e-brake is the only thing that gives us troubles; mostly from customers leaving them on. We are working on a few e-brake improvements. One uses two calipers on the rear rotors, the other uses the Explorer style drum in the rotor. After more R&D I will post some pics.