Ram Powergrip HD clutch sets are the ultimate for extreme street/strip performance. Using their proprietary 900 Series friction material in conjunction with increased clamp load pressure plates, you get maximum holding power for the track or street, with only minimal reduction in drivability. These are the clutch sets for big power street cars! Some clutch chatter will occur on takeoff. The Ram Powergrip HD clutch sets are designed for use with RAM billet steel or factory nodular iron (explosion-resistant) flywheels.