Forged Super Duty series for the Milwaukee Eight 114" and 117" engine for a 128" big bore conversion. Designed to work with both oil/water cooled engines and up to 3mm larger valves. With hard anodized crown and top ring groove to reflect heat and prevent ring to groove ''micro-welding''. The Line2Line abradable self-lubricating powder coating technique allows zero tolerance installation; final tolerance will be 0.003". The piston creates its own perfect tolerance during run-in; the coating automatically gives the tightest possible & perfect piston to cylinder fit for no piston rock and best possible ring seal. Note: Fits 114/117" M8 engines with stock 4.5" stroke. Aftermarket 4.25" bore cylinders are required. For up to 3mm larger valves. - Compression ratio: 11.7:1 - Engine displacement: 128" - Bore: 4.25" - Stroke: 4.5" - Ring Pack: 1.5mm; 1.5mm; 3.0mm - Top land: 0.23 - Pin Number: .927x2.250x.180c-SCR415H - Pin type: Floating - Pin Diameter: 0.927" - Lock: BR8894-1 - Compression height: 1.083" - Crown type: Dome - Crown (cc): -2.5 - Alloy: Forged 4032 alloy