80015 PowerForce 90015 PowerForce+Plus Fits 6.1L HEMI These are among the very few high performance dampers available for this engine and by far the least expensive. Our Powerforce model for high performance street applications is the only damper of this type available for this engine. The Powerforce+Plus is designed as a racing damper (but is more than suitable for street use as well) and meets SFI specfication #18-1 which is a requirement at most racing venues. As with all our Powerforce high performance street dampers, this model is made of tough nodular iron while the Powerforce+Plus SFI spec racing model is made of 1045 steel, both the hub and the ring. These dampers feature a special high performance elastomer bonded to the metal. Available June 2008.