DSS Racing FX Series Forged Piston Set

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

1-6840-4055C / 2-6840-4055C / 3-6840-4055C / K1-6840-4055C / K2-6840-4055C / K3-6840-4055C

Overview:

The DSS Racing Gen III Hemi FX Series Forged Piston Set is engineered for enthusiasts and professional builders seeking durable, high-performance pistons for Chrysler, Dodge, Jeep, and Ram 6.4L 392 engines. Designed to fit most 6.4L 392 small block Mopar Hemi Gen III engines, these pistons offer a perfect balance of strength, precision, and reliability for street, strip, or track applications.

With a 4.055" bore size and a compact 1.21" compression height, these forged pistons provide excellent compatibility with factory and aftermarket components. Their flat-top design with a -1.5cc volume optimizes combustion efficiency and power output, making them ideal for high-performance builds that demand consistent results under extreme conditions.

Key Features:

These pistons incorporate advanced engineering and quality materials to deliver superior performance and longevity. Key features include:

• Forged construction for enhanced strength and durability under high stress
• Flat-top piston design with a -1.5cc volume for optimized combustion chamber dynamics
• Pin diameter of .927" compatible with full-floating or press-fit configurations
• Ring groove dimensions of 1.2mm/1.2mm/3mm to accommodate high-performance piston rings
• Stroke compatibility of 3.720" and connecting rod length of 6.2" for precise engine geometry
• Available in multiple compression volumes (65cc, 74cc, 85cc) to suit various compression ratio requirements
• Designed specifically for the 384 Small Block Mopar Hemi Gen III platform
• Precision manufacturing ensures tight tolerances and consistent fitment

Construction & Design:

The DSS Racing FX Series pistons are crafted from high-grade forged aluminum alloy, providing an optimal combination of lightweight strength and thermal conductivity. This material choice helps reduce reciprocating mass while maintaining the structural integrity needed for high-RPM and high-boost applications. The pistons feature a carefully engineered flat-top profile with a slight dish to fine-tune compression ratios, enhancing combustion efficiency and power delivery.

Each piston is machined with precision ring grooves and pin bores to ensure proper sealing and minimal friction. The option for full-floating or press-fit wrist pins allows builders to tailor the setup to their specific engine build and performance goals. The robust design supports aggressive tuning and extended durability in demanding environments.

Installation & Fitment:

These pistons are designed to fit most Chrysler, Dodge, Jeep, and Ram 6.4L 392 Hemi Gen III engines with a 4.055" bore. Installation requires standard engine assembly procedures, and the pistons are compatible with factory or aftermarket rods featuring a 6.2" length and a 3.720" stroke. Builders should verify clearances and ring end gaps during installation to ensure optimal performance and longevity.

No major modifications are typically necessary, making these pistons a direct replacement or upgrade option for performance rebuilds and engine refreshes.

What's Included:

• Set of forged pistons (quantity as per kit selection)
• Compatible wrist pins (.927" diameter)
• Precision-machined ring grooves ready for high-performance piston rings

Ideal For:

• Performance engine builders upgrading 6.4L 392 Hemi Gen III platforms
• Street and strip enthusiasts seeking reliable forged pistons for high horsepower applications
• Motorsport participants requiring durable components for drag racing, road racing, or off-road use
• Engine rebuilders aiming to improve compression ratios and combustion efficiency

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.