If you’re planning on building the 4G63 to handle substantial amounts of horsepower and boost, then you should build the block with a set of Cosworth's Heavy Duty Connecting Rods. With over 50 years of racing heritage, they know what it takes to deliver an engine component that can sustain the perils of high performance driving. Like all of their connecting rods, these have been fabricated from 4340 steel, and have gone through the careful process of proprietary forging to maintain optimum weight and promote better strength.