SBC 4340 Forged Crank - 3.875 Stroke

The EAGLE SBC 4340 Forged Crank with 3.875 stroke is a premium forged steel crankshaft engineered for small block Chevy engines requiring a reliable, internally balanced bottom-end component. Built from 4340 steel, this crankshaft delivers the strength and fatigue resistance demanded by high-performance engine builds, street applications, and competition platforms where durability under load is non-negotiable.

The 3.875-inch stroke specification defines the piston travel distance within the cylinder bore, directly influencing engine displacement, torque characteristics, and rev capability. Internal balancing eliminates the need for external counterweights, simplifying installation and reducing rotating mass—a critical advantage in builds prioritizing efficiency and responsive throttle response. The 1-piece rear seal design streamlines assembly and reduces potential oil leak points compared to split-seal configurations. Forged construction provides superior grain structure compared to cast alternatives, offering greater resistance to cracking under sustained high RPM operation or aggressive tuning.

This crankshaft suits engine builders, performance shops, and enthusiasts assembling SBC stroker kits, street machines, or track-focused powerplants. The 59.1-pound weight reflects the solid construction typical of forged cranks in this displacement range. Proper installation requires compatible pistons, rods, and timing components matched to the 3.875-stroke specification—planning the full bottom-end package before purchase ensures compatibility and optimal performance.

Small block Chevy platforms remain the foundation of American performance engine building due to aftermarket support, proven reliability, and cost-effectiveness. A forged crankshaft from EAGLE represents a core investment in engine longevity and consistent power delivery across diverse applications—from weekend cruisers to serious performance platforms.