DSS Racing FX Series Forged Pistons

Fits Most Chrysler / Dodge / Jeep / Ram 6.4L 392 Gen III Mopar Hemi

1-6845-4085C / 2-6845-4085C / 3-6845-4085C / K1-6845-4085C / K2-6845-4085C / K3-6845-4085C

Overview:

The DSS Racing FX Series Forged Pistons are precision-engineered performance components designed specifically for the 6.4L 392 Gen III Mopar Hemi engines found in many Chrysler, Dodge, Jeep, and Ram models. These pistons deliver exceptional strength and durability, making them an ideal upgrade for enthusiasts seeking to enhance engine reliability and power output under demanding conditions.

Crafted for both street and track applications, these forged pistons offer improved resistance to heat and stress compared to stock cast pistons. Whether you are building a high-performance street machine or a race-ready engine, the DSS Racing FX Series pistons provide the foundation for consistent, reliable performance.

Key Features:

Designed with advanced engineering and quality materials, the DSS Racing FX Series Forged Pistons include the following key features:

• Compatible with 4.085" bore size for 6.4L 392 Gen III Mopar Hemi engines
• Comp height of 1.21" for optimal piston-to-head clearance and compression ratio tuning
• 18cc dish top design to support various combustion chamber volumes and compression ratios
• .927" wrist pin diameter available in full-floating or press-fit configurations
• Precision ring grooves sized at 1.2mm/1.2mm/3mm for reliable ring sealing and reduced blow-by
• Stroke compatibility of 3.720" and connecting rod length of 6.2" for balanced piston dynamics
• Approximate compression ratios ranging from 8.16 to 9.72 depending on combustion chamber volume (65cc, 74cc, 85cc)
• Forged construction for superior strength and fatigue resistance under high-performance conditions
• Engineered specifically for the 390 Small Block Mopar Hemi Gen III platform

Construction & Design:

The DSS Racing FX Series pistons are forged from high-grade aluminum alloy, providing an excellent strength-to-weight ratio essential for high-revving engines. The forging process enhances the grain structure of the metal, resulting in pistons that resist cracking, scuffing, and thermal distortion.

The pistons feature a carefully engineered dish top design with an 18cc volume reduction, allowing for precise control over compression ratios to suit different performance goals. The ring grooves are machined to tight tolerances to ensure optimal ring fitment and sealing, which helps maintain power and reduce oil consumption.

Available with either full-floating or press-fit wrist pins, these pistons offer flexibility for various engine builds and preferences. The combination of a 3.720" stroke and 6.2" connecting rod length ensures balanced piston speed and reduced side loading, contributing to engine longevity and smooth operation.

Installation & Fitment:

These DSS Racing FX Series Forged Pistons are designed as direct replacements for the 6.4L 392 Gen III Mopar Hemi engines used in many Chrysler, Dodge, Jeep, and Ram vehicles. Installation requires standard engine rebuild procedures, including proper honing of the cylinder bores to the specified 4.085" bore size.

Depending on the wrist pin option chosen (full-floating or press-fit), installation may require specific pin retention methods. It is recommended to have a professional engine builder or experienced technician perform the installation to ensure correct piston ring orientation, torque specifications, and clearances are met for optimal performance and reliability.

What's Included:

• Set of forged pistons sized for 4.085" bore
• Wrist pins (.927") in either full-floating or press-fit configuration
• Precision-machined piston rings sized 1.2mm/1.2mm/3mm
• Installation instructions and technical specifications

Ideal For:

The DSS Racing FX Series Forged Pistons are ideal for performance enthusiasts, engine builders, and racers who demand enhanced durability and power from their 6.4L 392 Gen III Mopar Hemi engines. Whether upgrading a factory engine for increased boost, nitrous, or naturally aspirated power, these pistons provide a reliable foundation for high-performance builds.

They are well-suited for street performance, drag racing, road racing, and other motorsport applications where engine strength and consistent compression are critical.

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.