4.185in Bore Forged Piston Set

The AutoTec Oldsmobile 455 Forged Piston Set (Part #1000586) is engineered for enhanced performance in Oldsmobile 455 engines. These pistons are crafted from a forged 4032 low-expansion, high-silicon aluminum alloy, offering excellent durability and suitability for street and strip applications. The set includes flat-top pistons with two valve reliefs, designed for a 4.185-inch bore and a 4.250-inch stroke. Key specifications include a compression height of 1.750 inches, a wrist pin size of 0.980 inches, and CNC-machined ring grooves that accept 1.5mm top ring, 1.5mm second ring, and 3.0mm oil ring sizes. The pistons also feature diamond-turned skirts for reduced friction. Compression ratios vary based on combustion chamber volume: 12.3:1 with 72cc chambers, 11.3:1 with 80cc chambers, and 10.6:1 with 87cc chambers. This set is sold as a set of 8 pistons and comes with pin fit, wire locks, broached pin oilers, and accumulator grooves. Please note that rings are sold separately.