Hotchkis Sport Suspension 4012 1970 - 1973 CamaroFirebird Sub Frame Connectors. The Hotchkis Performance sub - frame connectors for 70 - 73 F - Body cars are designed to add rigidity to the chassis to improve vehicle performance by reducing chassis flex. Fabricated from 1.5 in. x 3 in. .120 wall rectangular steel these TIG - welded connectors are powder coated gloss black. Installation of these connectors does not require modifications or cutting of the floor boards. The rear mount is a weld in while the front mount is a bolt in with the option to weld. This is a must have finishing touch for any F - Body restoration. Features Powder Coated Gloss Black Finish TIG - welded Fabricated from 1.5 in. x 3 in. .120 wall rectangular steel. Rigidly connects the front subframe to rear chassis frame rail which dramatically reduces chassis flex during hard cornering and acceleration. Does not require cutting or modifying the floor. Front is optional weld or bolt - on. Allows for front subframe removal if needed. Tucked - in design gives excellent ground clearance. Benefits Improves vehicle handling. Improves vehicle traction. Reduced chassis flex.