** IF NOT IN STOCK, CAN BE EASILY ORDERED Professional Series forged racing pistons from Wiseco are no-expense-spared pistons designed for the serious racers and builders. Packed full of custom-level performance and durability features and provided with premium rings, Professional Series pistons are designed and built for use in heavy to severe duty race builds. Remove your limits with Wiseco’s Professional Series. Engineered, forged, and machined in the USA from 2618 aluminum for improved tensile strength ArmorGlide Skirt Coating: seizure resistant, friction reduction, and quieter operation Fully machined crown features Precision ring grooves, anti-detonation groove, and additional ring seal improving features Forced pin oiling Designed and built to withstand heavy to severe duty performance applications 1.0/1.2/2.8mm Ring Thicknesses included Wiseco Chrysler 6.1L Hemi Piston Set, 4.080 in. Bore, 1.220 in. Compression Height, 0.984 in. Pin Diameter, Professional, Set of 8. .984" Pin Diameter designed for use with stock connecting rods. Compression Ratio at 0 Deck with .040 Gasket, 4.060" Bore Size and 4.100"gasket bore size.  3.580" Stroke 6.243" Rod Length Compression Ratio at: 65cc = 10.3, 73cc = 9.5