John "Fingers" McElravy created the biggest breakthrough in Duramax Piston design. Fingers Oval Bowl design utilizes the latest in heat mapping technology to disperse heat and keep more material in the right places, making then the go to pistons for the hardcore enthusiast. Starting with new Mahle Cast pistons, Fingers can build them to your specifications. Stock and overbore sizes, valve reliefs, or no valve reliefs. The compression ratio can range from 15.5:1 - 18:1. These cast pistons are able to be run in a high horsepower daily driver set up for the ultimate in longevity and performance.