DSS Racing FX Series Forged Piston Set

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

1-6845-4125C / 2-6845-4125C / 3-6845-4125C / K1-6845-4125C / K2-6845-4125C / K3-6845-4125C

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 offer a reliable upgrade for enthusiasts seeking enhanced durability and performance. Crafted to meet the demanding conditions of high-performance and street applications, this piston set provides improved strength and thermal resistance compared to stock cast pistons.

Ideal for builders and tuners working on the 398 Small Block Mopar HEMI Gen III platform, these pistons accommodate a 4.125" bore and are optimized for a 3.720" stroke with a 6.2" rod length. Whether you are rebuilding or upgrading your engine, the DSS Racing FX Series pistons deliver precision fitment and consistent performance.

Key Features:

These forged pistons incorporate advanced design elements to ensure durability and efficiency under high-stress conditions. Key features include:

• Forged construction for superior strength and fatigue resistance
• Compensated height of 1.21" for optimal piston-to-deck clearance
• 18cc dish top design to control compression and support various combustion chamber volumes
• .927" wrist pin diameter compatible with full-floating or press-fit configurations
• Ring groove dimensions of 1.2mm top and second rings, with a 3mm oil ring groove for effective sealing
• Designed for a 3.720" stroke and 6.2" connecting rods, matching factory and performance builds
• Approximate compression ratios tailored for different combustion chamber sizes: 65cc (9.88:1), 74cc (9.09:1), and 85cc (8.29:1)
• Precision machining ensures consistent fitment and performance across all pistons in the set

Construction & Design:

The DSS Racing FX Series pistons are forged from high-quality aluminum alloy, providing a lightweight yet robust component capable of withstanding the rigors of high-performance engines. The forging process enhances grain structure and mechanical properties, resulting in pistons that resist cracking and deformation under extreme heat and pressure.

The dish-top design with a -18cc volume helps manage compression ratios, making these pistons versatile for various tuning setups. The piston pin bore is engineered to accept either full-floating or press-fit pins, allowing flexibility depending on engine build preferences. Additionally, the ring grooves are precision-cut to accommodate standard ring sizes, ensuring optimal sealing and oil control.

Installation & Fitment:

This piston set is designed to fit most Chrysler, Dodge, Jeep, and Ram 6.4L 392 engines, specifically the 398 Small Block Mopar HEMI Gen III platform. Installation requires standard engine rebuilding procedures, including proper honing of the cylinder bore to 4.125" and ensuring compatibility with the 3.720" stroke crankshaft and 6.2" connecting rods.

Due to the precise engineering and OEM-compatible dimensions, these pistons typically install without the need for custom modifications. However, professional installation and careful measurement are recommended to achieve optimal piston-to-wall clearance and ring end gap settings.

What's Included:

• Complete set of forged pistons sized for 4.125" bore
• Compatible with full-floating or press-fit wrist pins (pins not included)
• Precision-machined ring grooves for standard piston rings

Ideal For:

This piston set is ideal for performance enthusiasts, engine builders, and professional tuners upgrading or rebuilding Chrysler, Dodge, Jeep, and Ram 6.4L 392 HEMI engines. Whether for street performance, track use, or mild racing applications, these forged pistons provide enhanced durability and reliability over stock components.

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.