Wiseco K656M865AP 1400HD Forged Piston Kit 86.5mm Bore 10.5:1 CR Mitsubishi 4G64 w/ 4G63 Head E85

The Wiseco K656M865AP is a Professional Series 1400HD forged piston kit engineered for high-output, turbocharged Mitsubishi 4G64 engines running 4G63 cylinder heads. Built on Wiseco's heavy-duty strutted forging platform, this kit is purpose-built to handle the extreme cylinder pressures associated with E85 ethanol fuel, large-frame turbochargers, nitrous oxide, and methanol injection — all while maintaining the tight tolerances required for reliable high-horsepower builds.

Each piston is forged in-house at Wiseco's Mentor, Ohio facility from 2618 aerospace-grade aluminum alloy, chosen for its superior strength-to-weight ratio, excellent fatigue resistance, and ability to withstand high operating temperatures. The strutted 1400HD forging design reinforces the pin boss area to resist deformation under severe loads, making this kit suitable for builds producing 350+ horsepower per cylinder.

Key Features:

• Bore: 86.5mm (+0.06mm oversize)
• Compression Ratio: 10.5:1 — optimized for E85 fuel
• Stroke: 88mm (3.465 in)
• Rod Length: 150mm (5.906 in)
• Compression Height: 35mm (1.378 in)
• Block Height: 229mm
• Pin Diameter: 22mm tool steel floating wrist pin (included)
• Piston Weight: 394 grams
• Piston Dish Volume: -4.5cc
• Piston Material: 2618 aerospace aluminum alloy
• Skirt Coating: ArmorGlide® — reduces friction, minimizes noise, and frees up horsepower
• Specially designed multi-valve pockets and optimized crown shape
• Steel nitride/Napier XX ring set included

Kit Includes:

• 4x Forged Pistons
• 4x Tool Steel Wrist Pins (Pin P/N: S722)
• 8x Wire Locks
• 4x Ring Sets (Ring P/N: 8650XX)

Replacement/Service Parts:

• Replacement Pin: S722
• Replacement Rings: 8650XX

Wiseco's ArmorGlide® skirt coating is applied as a standard feature, delivering reduced friction between the piston skirt and cylinder wall — translating to lower operating temperatures and more usable power. The multi-valve pockets and complex crown geometry are precision-machined to maintain proper valve clearance when pairing the 4G64 long-stroke block with 4G63 cylinder heads, a popular configuration in DSM and Mitsubishi performance builds.