PRO/STREET dampers are not intended for racing, the fact that they are cast of nodular iron, as opposed to ordinary gray iron, means that they are suitable for higher rpms than most competitive models. (Note: The PRO/STREET Nodular Iron Harmonic Dampers are NOT SFI certified). However to prove the integrity of the PRO/STREET dampers, Pro Race Products had the SFI test lab run some spin tests. The PRO/STREET damper was subjected to 8,000rpm for one hour, and then 12,500rpm for 15 minutes with no sign of degradation! Unlike many OE dampers, or other replacement style dampers, the PRO/STREET range feature a bonded elastomer! The elastomer is injected at high temperature and under extreme pressure. In fact during the manufacturing process EACH AND EVERY PRO/STREET damper is subjected to elastomer bond test of 3000lbs separation force. If there is any sign of bond degradation then the damper is scrapped. Many OEM dampers aren't bonded at all.