The X-Beam forging design produces a stronger piston than most standard pistons for the ultimate in performance. All Howards HRC Racing Pistons are forged from 2618 billet bar stock and then heat treated and aged to a T61 condition (2618-T61). This material has less than 1% silicon particulate content. High silicon content pistons (forged from 4032 or MS75) will not stand up to the most extreme stress placed on many racing pistons. If a crack starts to form in a high silicon piston it will continue until the piston experiences a catastrophic failure. Simply stated, adding sand to the aluminum only makes it more brittle. Another advantage of 2618-T61 over the high silicon pistons is the ability to keep its shape under extreme pressure and high RPM’s. “Skirt Shrinking” is not a problem with Howards HRC Racing Pistons. Standard features include CNC turned skirts, oversized valve pockets with radius valve reliefs, forced pin oilers, accumulator grooves and lock removal indents. Sets include lightweight (108g) .150” wall, heat treated aircraft quality wrist pins. Double spirolox are standard.