The rear block kits by Superlift include a pair of cast iron blocks with 4 u-bolts, nuts and washers. These components are the same as are used with the Superlift lift kits. All blocks are tapered to address driveshaft angle, length and alignment unless otherwise noted. U-bolts are manufactured using low alloy, high strength steel with an anti-corrosion finish of either zinc or E-coat. U-bolt nuts are aircraft type, Nylon inserted locking nuts. U-bolt flat washers are Phosphate coated, heat treated an extra thick.