Attributes . Forged from high-silicon aluminum alloy for maximum strength and dependability.. Innovative forging design and piston skirt provide maximum horsepower and torque.. Wiseco High-Performance piston kits are priced with piston, rings, pins and circlips (unless noted otherwise).. Oversize pistons require cylinder sleeving.. SPECIFICATIONS. Bore - Actual: 57.5mm. Compression Ratio - Actual: 10:1 CR. Skirt Coating . Values