About this item Special Fits for Small and Big Block Chevy engines.Also fits Corvette,Camaro,Caprice,Chevelle,Bel-Air,Biscayne,Trans Am,Firebird,Impala,El Camino,Nova . Replaces O.E. part numbers: 3990914 3960768 6258154 Features a Red polyurethane construction,Specially deigned to be much stronger than OE rubber mounts,They are tough like solid metal mounts without the vibration and noise. 2-9/16″ between mounting frame tower mounting tabs. Limits unwanted movement thereby putting more power to the wheels