Forged Piston Set, 4.000in Bore, -25cc Dish Top

The DSS Racing 5917-4000 is a premium forged piston set engineered for the Ford 300 L6 6-cylinder engine. Designed with a 4.000-inch bore and a -25cc dish top, these pistons are built to enhance performance in a variety of applications. Key features include a brushed piston crown for improved durability, extensive CNC milling in non-critical areas to reduce weight, and the patented “X Groove” skirt design, which promotes superior cylinder and ring longevity. These pistons boast a 1.200-inch compression height and a 0.912-inch pin diameter, with a 3.980-inch crankshaft stroke and a 6.800-inch connecting rod length. The TDC assembly height is 9.990 inches, indicating a zero deck height. The product specifications also note that most L6-series OEM connecting rods may require narrowing at the pin end for proper side clearance within the 2.5-inch pin boss; aftermarket rods often feature a narrower profile and do not require this modification. Available options include different piston series (FX-1, FX-2, FX-3) and whether the set includes DSS Racing piston rings. All DSS Racing forged pistons are proudly forged and machined in the USA.