DSS Racing FX Series Forged Piston Set

Fits Most Chrysler / Dodge / Jeep / Ram 6.4L 392 Models

1-6847-4090C / 2-6847-4090C / 3-6847-4090C / K1-6847-4090C / K2-6847-4090C / K3-6847-4090C

Overview:

The DSS Racing FX Series Forged Piston Set is engineered specifically for the Chrysler, Dodge, Jeep, and Ram 6.4L 392 HEMI engines. Designed to fit most 6.4L 392 models, these pistons are crafted to deliver superior strength, durability, and performance for high-output small block Mopar HEMI Gen III engines. Whether you are building a high-performance street machine or a race-ready engine, these forged pistons provide the reliability and precision needed to handle increased power and boost levels.

With a bore size of 4.090 inches and a compression height of 1.21 inches, this piston set features a +4cc dome top design that optimizes combustion chamber volume and compression ratio. The pistons are compatible with full-floating or press-fit wrist pins, allowing for flexible installation options based on your engine build preferences.

Key Features:

These DSS Racing forged pistons incorporate advanced design elements and materials to ensure maximum performance and longevity:

• Forged construction for enhanced strength and resistance to high stress
• +4cc dome top design to optimize combustion efficiency and compression ratios
• Compatible with full-floating or press-fit wrist pins (.927" pin diameter)
• Ring groove dimensions: 1.2mm top and second rings, 3mm oil ring for effective sealing
• Designed for 3.720" stroke and 6.2" connecting rods, matching factory specifications
• Available compression ratios approximately 12.5:1 (65cc), 11.18:1 (74cc), and 9.94:1 (85cc) depending on dome volume
• Precision machining ensures tight tolerances and consistent performance
• Ideal for high-performance builds requiring durability under increased cylinder pressures

Construction & Design:

The DSS Racing FX Series pistons are forged from premium-grade aluminum alloy, providing an excellent balance of lightweight construction and high tensile strength. The forging process refines the metal grain structure, resulting in pistons that resist cracking, scuffing, and thermal fatigue even under extreme operating conditions.

The dome top design with a +4cc volume enhances combustion chamber dynamics, improving power output and throttle response. The pistons feature carefully engineered ring grooves that accommodate high-performance piston rings, ensuring optimal sealing and oil control. The wrist pin bore is precision-machined to accept either full-floating or press-fit pins, offering versatility for various engine assembly methods.

Installation & Fitment:

This piston set is designed to fit most Chrysler, Dodge, Jeep, and Ram 6.4L 392 HEMI engines, making it a direct replacement for factory pistons in these applications. Installation requires standard engine assembly procedures, and the pistons are compatible with the factory stroke of 3.720 inches and 6.2-inch connecting rods. Depending on your build, you may need to verify clearances and ring end gaps to ensure proper fitment and performance.

These pistons are suitable for both rebuilds and performance upgrades, providing a reliable foundation for increased horsepower and torque without compromising engine longevity.

What's Included:

• Set of four DSS Racing FX Series forged pistons (4.090" bore)
• Compatible with full-floating or press-fit wrist pins (pins not included)
• Precision-machined ring grooves for 1.2/1.2/3mm piston rings (rings not included)

Ideal For:

This piston set is ideal for automotive enthusiasts, engine builders, and professional racers who demand durable, high-performance components for their 6.4L 392 HEMI engines. Whether upgrading a street vehicle for improved power delivery or building a race engine capable of handling high boost and RPM, these forged pistons provide the strength and reliability necessary for serious performance applications.

DSS Racing — Founded in 1983 originally as Danny’s Speed Shop, DSS Racing has grown from a small Midwest performance engine shop into a respected name in forged engine components for the high-performance and racing markets. Based in St. Charles, Illinois, DSS is best known for its forged pistons and machined engine parts made in the USA that have been used in championship engines and thousands of builds, blending old-school racing roots with precision manufacturing for enthusiasts and racers alike.