Wiseco K398X05 Forged 4.005" Pistons for GM LS V8 (-3.2 cc Flat Top)

Vehicle Fitment

• GM LS-series V8 engines (Gen III / IV)

Features

• Forged from high-strength 2618 aluminum alloy
• ArmorGlide® skirt coating to reduce friction and improve durability
• Anti-detonation and pressure-seal grooves to enhance ring sealing
• Flat-top piston design with -3.2 cc crown volume
• 0.927" floating wrist pin for reliability under high load
• Designed for NA, nitrous, or boosted applications
• Precision valve reliefs compatible with LS-style cylinder heads
• Complete ring set included to ensure optimal sealing

Specifications

• Bore Diameter: 4.005 in
• Stroke: 3.622 in
• Compression Height: 1.304 in
• Piston Volume: -3.2 cc (flat-top)
• Rod Length Compatibility: 6.125 in
• Wrist Pin Diameter: 0.927 in
• Piston Ring Grooves: 1.2 mm / 1.2 mm / 3.0 mm
• Average Weight: ~467 g per piston

Included Components

• 8 x Forged pistons (K398X05)
• 8 x Floating wrist pins (0.927")
• 16 x Retaining clips / Spirolox
• 8 x Ring sets (1.2 / 1.2 / 3.0 mm)

Product Description

The Wiseco K398X05 is a professional-series forged piston kit tailored for GM's LS V8 engines. With a 4.005" bore, 3.622" stroke, and a -3.2 cc flat crown, these pistons help maintain a moderate compression ratio while providing strength and reliability for performance builds.

Made from 2618 forged aluminum, the K398X05 offers excellent durability under high thermal and mechanical load. Its ArmorGlide® coated skirts reduce friction and protect against wear, while the anti-detonation and pressure-seal grooves ensure a tight ring seal for consistent power delivery.

Supplied as a full 8-piston set, this kit is ideal for engine builders undertaking a complete top-end rebuild. Proper installation involves checking ring end gap, piston-to-wall clearance, and clearance to head to ensure optimal performance and longevity.