This is the 5.400-inch Eagle "SIR" I-beam connecting rod with cap screw security, which is better than the original C3OE connecting rods with 5/16-inch bolts. What makes it better is 5140 steel alloy for optimum strength. Pin boss is available in either press fit or floating. The ARP 3/8-inch cap screws are indestructible. Eagle has matched this set to within plus or minus 2 grams. These rods are rated to 500 horsepower, which makes them perfect for our 350-horse small-block.