DSS Racing FX Series Gen III Hemi Forged Piston Set

Fits Most Chrysler / Dodge / Jeep / Ram 6.1L SRT8 Models

1-6840-4090D / 2-6840-4090D / 3-6840-4090D / K1-6840-4090D / K2-6840-4090D / K3-6840-4090D

Overview:

The DSS Racing FX Series Gen III Hemi Forged Piston Set is engineered specifically for Chrysler, Dodge, Jeep, and Ram vehicles equipped with the 6.1L SRT8 engine. Designed to handle the rigors of high-performance applications, these pistons offer exceptional strength and durability while maintaining optimal weight for improved engine response. Whether you are rebuilding your engine or upgrading for enhanced power and reliability, this piston set delivers precision fitment and performance consistency.

Ideal for enthusiasts and professional builders alike, these pistons support aggressive tuning and increased boost levels, making them a reliable choice for street, strip, or track use. Their forged construction ensures superior resistance to heat and stress compared to cast pistons, providing peace of mind under demanding conditions.

Key Features:

Built to exacting standards, the DSS Racing FX Series pistons incorporate advanced design elements to maximize performance and longevity:

• Compatible with 4.090" bore size for most 6.1L SRT8 engines
• Forged construction for enhanced strength and durability
• Flat top design with a -1.5cc dish for optimized combustion chamber volume
• Compression height of 1.21" tailored for Gen III Hemi applications
• .927" wrist pin diameter with options for full-floating or press-fit installation
• Ring groove dimensions: 1.2mm top and second rings, 3mm oil ring for effective sealing
• Stroke compatibility of 3.578" and connecting rod length of 6.243" for precise engine geometry
• Available in multiple combustion chamber volume options to suit different compression ratios (65cc, 74cc, 85cc)
• Designed to support compression ratios ranging approximately from 9.06:1 to 11.2:1

Construction & Design:

Each piston in the FX Series is forged from high-grade aluminum alloy, providing an excellent balance of lightweight construction and mechanical strength. The forging process refines the metal grain structure, resulting in pistons that resist cracking and deformation under extreme thermal and mechanical loads. The flat top with a slight dish enhances combustion efficiency and helps control detonation in high-compression setups.

The pistons feature precision-machined ring grooves and pin bores to ensure optimal sealing and minimal friction. The option for full-floating or press-fit wrist pins allows builders to tailor the assembly to their specific engine build and performance goals. This attention to detail in design and manufacturing ensures reliable operation in demanding environments.

Installation & Fitment:

These pistons are designed as direct replacements for most Chrysler, Dodge, Jeep, and Ram 6.1L SRT8 engines with a 4.090" bore. Installation requires standard engine rebuilding procedures, including proper honing and cleaning of the cylinder bores. Depending on the wrist pin option selected, either full-floating or press-fit installation methods should be followed according to engine builder preferences and specifications.

Due to their precise dimensions and compatibility, these pistons fit seamlessly into Gen III Hemi configurations without the need for extensive modifications, making them an excellent choice for performance upgrades or engine rebuilds.

What's Included:

• Set of forged pistons sized for 4.090" bore
• Wrist pins (full-floating or press-fit depending on SKU)
• Ring grooves machined to accept 1.2/1.2/3mm piston rings (rings not included)

Ideal For:

This piston set is ideal for performance enthusiasts, professional engine builders, and racers seeking a durable, high-quality piston solution for the 6.1L SRT8 engine platform. It supports high compression and aggressive tuning, making it suitable for street performance, drag racing, road racing, and other motorsport applications where reliability and power are paramount.

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.