Eagle 428135435933 Forged 4340 Steel Crankshaft Ford 4.6L Modular 3.543" Stroke

Vehicle Fitment

• Universal - Fits all Ford 4.6L Modular V8 variants (2V Romeo, 2V Windsor, 3V, 4V) using a 3.543" stroke, 2.086" rod journals, 2.657" main journals, and a minimum 5.933" connecting rod length with 1-piece rear main seal and 8-bolt flywheel flange

Fitment Notes

• This is a universal crankshaft - no specific vehicle year or trim fitment is assigned; builder must verify all block, rod, piston, and bearing compatibility before installation
• Fits all Ford 4.6L Modular cylinder head configurations: 2-valve Romeo, 2-valve Windsor, 3-valve, and 4-valve (Cobra/GT500-style)
• Block clearancing is required when installing this crankshaft in 2-valve 4.6L blocks - verify sufficient rotating clearance in the block before final assembly
• Requires an 8-bolt flywheel flange - use an 8-bolt Cobra-style flywheel or flexplate; confirm your flywheel/flexplate bolt pattern before ordering
• 3.543" stroke matches the stock Ford 4.6L Modular stroke - this is a direct forged upgrade over the OEM cast crankshaft, not a stroker
• Requires chamfered or narrowed main and rod bearings - Eagle's .125" fillet radius on all journals is larger than OEM; standard OEM-profile bearings will contact the fillet and cannot be used
• 1-piece rear main seal design - confirm your block uses a 1-piece rear seal before ordering
• Minimum connecting rod length: 5.933" - confirm your connecting rod center-to-center length meets this requirement
• Crankshaft MUST be precision-balanced to match your specific connecting rods and pistons before installation

Features

• Forged 4340 steel construction - forged from certified SAE 4340 chromium-molybdenum-nickel alloy steel using a non-twist forging process; the non-twist method orients the metal grain along the crankshaft's length for superior torsional strength compared to standard twist-forged or cast cranks
• Center-counterweighted design - counterweights are positioned at the center of the crankshaft throw for improved rotational stability at high RPM and high-power outputs, reducing harmonic vibration and improving crankshaft longevity under sustained competition loads
• Multi-stage heat treatment process - includes stress relief and shot peening for improved internal material consistency and fatigue life from the inside out
• X-rayed, magnafluxed, and sonic-tested - every Eagle forged crankshaft undergoes full non-destructive inspection to verify structural integrity before leaving the factory
• Nitrided surface treatment - all journals and fillets are nitrided for maximum surface hardness and superior wear resistance throughout the crankshaft's service life
• Micropolished to less than 2 Ra - journal surfaces are micropolished below 2 Ra for optimal hydrodynamic bearing oil film formation and reduced bearing wear under high-load operation
• .125" fillet radius on all journals - substantially larger than OEM fillet radii, improving torsional rigidity and fatigue resistance at the journal-to-web transition under high-power and high-RPM conditions
• Chamfered oil holes - oil feed holes are chamfered for improved oil flow to rod and main bearings, reducing starvation risk at high RPM
• Target bobweight of 1600g ±2% - pre-set bobweight significantly reduces the time and cost required for final dynamic balancing when paired with appropriate rods and pistons
• Rated to support up to 1500 HP - suitable for naturally aspirated, forced induction, nitrous, and exotic fuel competition applications
• Internally balanced - designed for internally balanced 4.6L Modular assemblies; no external counterweighting on the flywheel or damper is intended
• Typical weight: 50 lbs

Specifications

• Part Number: 428135435933
• Material: Forged 4340 Steel (Non-Twist Forging)
• Application: Ford 4.6L Modular V8 (2V Romeo, 2V Windsor, 3V, 4V)
• Stroke: 3.543" (90mm - Stock Stroke)
• Rod Journal Diameter: 2.086"
• Rod Journal Width: 1.900"
• Main Journal Diameter: 2.657"
• Minimum Rod Length: 5.933"
• Intended Balance: Internal
• Target Bobweight: 1600g ±2%
• Oiling Design: Standard
• Rear Seal Design: 1-Piece
• Flywheel Bolt Holes: 8 (8-Bolt Cobra Flywheel Required)
• Counterweight Style: Center-Counterweighted
• Fillet Radius: .125"
• Bearing Requirement: Chamfered or Narrowed Bearings Required
• Surface Treatment: Nitrided, Micropolished to <2 Ra
• Horsepower Rating: Up to 1500 HP
• Typical Weight: 50 lbs

Included Components

• 1x Eagle Forged 4340 Steel Crankshaft (428135435933)
• Note: Connecting rods, pistons, bearings, flywheel, damper, and all other engine components are NOT included and must be sourced separately. Precision balancing to match your specific rods and pistons is required before installation and is not included.

Product Description

The Eagle 428135435933 is a forged 4340 steel center-counterweighted crankshaft for the Ford 4.6L Modular V8, retaining the stock 3.543" stroke while delivering significantly superior material strength and construction quality compared to the factory cast crankshaft. It covers all 4.6L Modular cylinder head configurations - 2-valve Romeo, 2-valve Windsor, 3-valve, and 4-valve - making it the foundational bottom-end component for high-output 4.6L builds that demand more than the OEM crank can reliably provide under sustained boost, nitrous, or high-RPM competition conditions.

The forging uses a non-twist process, which orients the metal grain along the crankshaft centerline for superior torsional strength relative to standard twist-forged or cast alternatives. Center-counterweights are positioned at the center of each throw to improve rotational stability at high RPM and reduce harmonic vibration under load. Every crankshaft undergoes a multi-stage heat treatment including stress relief and shot peening, followed by X-ray, magnaflux, and sonic inspection - Eagle's full non-destructive evaluation suite - to verify structural integrity before leaving the facility. Journals are then nitrided for surface hardness and micropolished to less than 2 Ra for optimal bearing oil film maintenance.

The .125" fillet radius on all rod and main journals requires the use of chamfered or narrowed bearings - standard OEM-profile bearings cannot be used. Block clearancing is required when installing this crank in 2-valve 4.6L blocks, and the 8-bolt flywheel flange requires a Cobra-style 8-bolt flywheel or flexplate. Target bobweight is preset to 1600g ±2%, substantially reducing the time and labor required for final dynamic balancing. This crankshaft is rated to support up to 1500 HP and must be precision-balanced to match the specific connecting rods and pistons used in the build before installation.