This item is for a Bundled set of (8) Standard size or 4.00 inch bore diameter hypereutectic flat top pistons with 4 valve reliefs including lock rings for floating pins and a matching moly piston ring set compatible with 1968-85 Chevy 350 cid (5.7L) small block V-8 engines. These pistons can be used as a performance upgrade in engines originally equipped with dish top pistons without modifications. These pistons are designed for either press fitted or floated connecting rods. Lock rings are not inclided and must be purchased separately. Piston specifications: Bore: 4.00 inch Stroke: 3.480 in. (stock) Connecting Rod Length: 5.700 in. (stock); rods Not included Piston Top Style: Flat top with 4-valve reliefs Compression Height: 1.548 in. Piston Material: Hypereutectic aluminum Wrist Pin Diameter: .927 in.; pins included Wrist Pin Style: Press-fit or floating; Pin clips included Ring Land Sizes: 5/64-5/64-3/16 (oil ring); Rings included Notes: DurOshield coated skirts. Usage: Stock, Street and mild strip RPM Range: Idle - 6,000 Compression Ratio (approximate): 10.2:1 w/58cc; 9.6:1 w/64cc; 8.5:1 w/76cc