These tubs are designed to make your job easy when putting wider tire and wheel combos on your Chevrolet or GMC pickup. Our 1955-72 version is actually designed as an exact replacement for 67-72 fleetside trucks, but it works great on stepside trucks looking for that extra clearance for wide wheels and tires. Both our 1955-72 AND our 1973-87 versions are over 16" wide! On most application this will give you at lease 5" extra inches of clearance and width.