DSS Racing FX Series Forged Piston Set

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

1-6847-4125C / 2-6847-4125C / 3-6847-4125C / K1-6847-4125C / K2-6847-4125C / K3-6847-4125C

Overview:

The DSS Racing FX Series +4cc Dome Top Forged Piston Set is engineered specifically for the 6.4L 392 HEMI engines found in Chrysler, Dodge, Jeep, and Ram vehicles. Designed to enhance performance and durability, these pistons are ideal for enthusiasts looking to upgrade their engine’s strength and efficiency. Featuring a +4cc dome top design, these pistons help optimize compression ratios for improved combustion and power delivery.

Built to meet the demands of high-performance applications, this piston set is perfect for street performance, racing, or heavy-duty use. Whether you are rebuilding your 6.4L HEMI or seeking a reliable upgrade, DSS Racing’s FX Series pistons offer a precision fit and robust construction to support your engine’s potential.

Key Features:

These forged pistons incorporate advanced design elements and materials to ensure maximum reliability and performance:

• +4cc dome top design to increase compression and improve combustion efficiency
• Compatible with 4.125" bore size for precise fitment in 6.4L 392 HEMI engines
• Forged construction for superior strength and resistance to high stress
• Pin diameter of .927" with options for full-floating or press-fit configurations
• Ring groove dimensions of 1.2mm/1.2mm/3mm to accommodate high-performance piston rings
• Designed for a 3.720" stroke and 6.2" connecting rods, matching factory specifications
• Available in multiple dome volumes (65cc, 74cc, 85cc) to tailor compression ratios from approximately 12.68:1 to 10.08:1
• Comp height of 1.21" for optimal piston-to-head clearance and combustion chamber compatibility

Construction & Design:

The DSS Racing FX Series pistons are crafted from high-grade forged aluminum alloy, providing an excellent balance of lightweight strength and thermal conductivity. The forging process enhances the metal’s grain structure, resulting in pistons that withstand extreme combustion pressures and temperatures without deformation.

The dome top design increases the piston’s compression volume, allowing for improved power output while maintaining engine reliability. Precision machining ensures tight tolerances for bore size, pin fitment, and ring grooves, guaranteeing smooth operation and reduced friction within the cylinder bore.

Installation & Fitment:

These pistons are designed as direct replacements for most Chrysler, Dodge, Jeep, and Ram 6.4L 392 HEMI engines with a 4.125" bore. Installation requires standard engine rebuild procedures, including proper ring end gap setting and piston pin installation. Depending on your engine build, you can select either full-floating or press-fit wrist pins to match your application.

Due to the +4cc dome volume, it is important to verify piston-to-valve clearance and compression ratio compatibility with your cylinder heads and camshaft setup. Professional installation is recommended to ensure optimal engine performance and longevity.

What's Included:

• Set of forged pistons with +4cc dome tops (quantity as per kit selection)
• Wrist pins (full-floating or press-fit depending on chosen option)
• Piston rings compatible with 1.2/1.2/3mm groove dimensions (may be sold separately)
• Installation instructions and technical specifications

Ideal For:

This piston set is ideal for automotive enthusiasts and professional builders upgrading or rebuilding 6.4L 392 HEMI engines seeking enhanced durability and performance. It suits street performance vehicles, drag racing, road racing, and other high-stress applications where forged components are essential for reliability and power gains.

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.