TOMEI CONROD BOLT SET For EVO 1-9 4G63 123004Brand TOMEI Product Number 123004 Compatible Car EVO 1 9 Compatible Engine 4G63 Product Description Extreme engine speeds with the increase of cylinder pressure and power will add an increased burden on the conrod bolts. The increased stroke length in most performance engines and increased piston speeds will also add more stress loads to the conrod bolts. Since the common weak points of the connecting rods are usually the conrod bolts itself.