ATK Ford 347 Stroker 410 HP HP20C-EFI Stage 3 EFI Engine

ATK Ford 347 Stroker – Windsor Street-Strip Application

The ATK Ford 347 Stroker 410 HP HP20C-EFI Stage 3 EFI Engine eliminates the fueling and airflow bottlenecks inherent in factory 302ci Windsor platforms. By pairing high-velocity aluminum cylinder heads with a digital EFI management system, this 5.7L unit solves the cold-start and altitude tuning issues common in carbureted stroker builds. The 347ci configuration provides optimized volumetric efficiency under EFI, allowing for precise ignition timing and consistent cylinder pressure management during aggressive street performance or track-day cycles.

Integrating this professionally mapped EFI architecture delivers a massive advantage by removing the variable costs of independent fuel system calibration and ECU wiring. Adopting this package saves approximately 62 hours of shop labor through its plug-and-play wiring harness and pre-configured computer system. This dyno-ready foundation ensures 410 HP consistency, offering shop owners a dependable 5.7L solution that significantly reduces the threat of component fatigue during the initial startup phase.

ATK High Performance HP20C-EFI Engineering Specifications

• The reciprocating assembly features a 5.7L by 347 cubic inch stroker dimension profile
• Peak performance reaches 410 HP output with high torque capacity
• Internal compression is set at 10.0:1 for optimal thermal efficiency
• Rotating components consist of high-tensile materials to maintain stability
• Cylinder head architecture utilizes aluminum for superior heat dissipation
• The block foundation uses cast iron to prevent cylinder wall distortion
• Valvetrain configuration follows hydraulic roller standards to ensure timing control

Ford 347 Stroker Power & BMEP Characteristics

The 347 cubic inch stroke anchors the torque peak in a broader RPM window than traditional 302 engine builds. This modification improves the instantaneous throttle response sensitivity, making the platform highly responsive for classic Mustang or Fox-body EFI swaps. Under electronic management, the BMEP remains stable, preventing detonation during rapid acceleration events while maintaining precise fuel delivery curves through the throttle body.

Material Integrity & Ford Windsor Durability

Durability is engineered through the combination of a high-rigidity iron block and lightweight aluminum heads. This hybrid construction eliminates thermal fatigue risks common in legacy all-iron engines when subjected to high-load stroker cycles. The external 28 oz. balancing process removes stress risers from the crankshaft, ensuring survival through extreme heat cycles typical of high-performance Ford environments where structural integrity is mandatory.

HP20C-EFI Drivetrain & Ford Windsor Integration

This engine bolts directly to Ford transmissions utilizing a 1-piece rear main seal and Windsor-specific bolt patterns. Because the assembly uses a 28 oz. external imbalance, builders must use the included harmonic balancer and flexplate. This prevents destructive torsional vibrations that could damage sensitive drivetrain bearings. The provided harness and sensors simplify integration with modern overdrive transmissions for improved highway cruising.

Ford 347 Stroker Street & Swap Versatility

This 347ci unit is a primary choice for Mustang restorations, Bronco conversions, and classic F-100 truck swaps. It maintains a 10.0:1 compression safety margin, allowing for worry-free operation on standard 91 octane pump fuel. The integrated EFI system ensures smooth idle quality and AFR stability, making 410 HP manageable in heavy traffic or during long-distance cruising without the maintenance of carburetors.

Fitment & Ford 347 Stroker Installation Protocol

Builders must confirm chassis clearance for the provided Ford oil pan and intake manifold height. The protocol requires routing the provided engine harness to the onboard computer to support the 410 HP peak output. Check accessory drive alignment against the provided water pump and timing cover. Professional priming of the lubrication system is mandatory before the first electronic ignition to protect bearings.

Warranty & Support Compliance

ATK High Performance stands behind this complete EFI build with a limited **12-month warranty** against defects in workmanship. Claims require documented professional installation and a completed warranty registration form. US-based tech support provides EFI calibration and startup guidance to safeguard this significant mechanical investment during the critical first 500 miles of operation.

Final installation and chassis compatibility must be verified against manufacturer’s current technical bulletin and vehicle-specific measurements.