Edelbrock part #4255 With Front Mounted Cam Sensor w/hole (LS2 and Later Model Trucks) These two-piece aluminum timing covers for GM Gen III IV LS Series allow quick camshaft removal and installation without the need to remove the damper pulley or steering components. The cam can be installed and removed through a window in the front of the cover which is sealed with a plate and O-ring for superior leak prevention. Not for use with a double roller timing chains.