Replaces factory engine mount for 75-81 F-Body. Extra Bolt holes will adapt a 61-69 2 bolt block to use in 70-81 F-body. These may require some modification or slight shifting of frame mounts for proper alignment. Both because of thickness of required adapter and/or “tweaks” in the frame over years of use, damage, etc. Kit includes 75-81 2387BP Billet frame mounts (pair). 75-81- Direct factory replacement. The ultimate in aftermarket frame mounts. Milled from 6061 billet aluminum. Features custom molded poly inserts with billet sleeves. Rated to 600+HP Improved design is much stronger and stable than factory motor mounts. Prevents excess engine movement and damage to other vehicle components. Made of HYPER-FLEX performance polyurethane. Resistant to under vehicle fluids: oils, coolants, road contaminants. Original engine height will not be altered with these mounts Includes mounting hardware If using headers, ceramic coated headers are highly recommended AND/OR a heat shield or header wrap to keep heat away from the Poly mounts as excessive heat may cause the poly to melt or deteriorate.