Who makes the pistons for 440source these days? I think they used Ross and Diamond in the past but nowadays they don't mention the manufacturer anymore?
Yes, we use United Engine and Machine (parent company of ICON forged pistons.) They've been around since the 1920's, are family owned and are right down the street from us here in Carson City, Nevada. They make a very good quality product. We only sell the 2618 premium forged pistons, (the same material as Ross, JE, Diamond, etc) we don't sell the Hypereutectic pistons (just to avoid any confusion.)
