ARP main cap bolt kit are the strongest main bolts you can buy for the big block Mopar engine. Made from start to finish right here in Southern California, they are forged from aircraft quality 8740 Chrome Moly steel, and have features like fully rolled threads and generous underhead radius, giving EACH BOLT a capacity of 180,000 pounds per square inch! Parallel ground and hardened washers (shown above) are also included. Finished in black oxide for good looks and corrosion resistance. For the super important job of holding the crank firmly in the block, you just can't buy a better bolt. Period.