ATK HP20 Ford 347 Stroker 410 HP Stage 1 Long Block Crate Engine

Description

Retain authentic small-block dimensions with the ATK HP20 Ford Crate Engine 347 Stroker Stage 1 package. Engineered for classic Mustangs, Fairlanes, and Cobra kit cars, this 5.7-liter Windsor stroker V8 produces 410 brake horsepower at 5,800 RPM. Lightweight aluminum cylinder heads and a matched hydraulic roller camshaft provide aggressive throttle response and high-revving power in a compact package.

Engine machinists hand-select seasoned Ford 302 cast iron blocks, clearance-notching cylinder bottoms before precision align-honing main journals. A cast nodular iron stroker crankshaft spins with external 28-ounce imbalance weighting inside a one-piece rear main seal casing. Forged steel connecting rods attach to 4.030-inch hypereutectic pistons across a 3.400-inch stroke. A 10.0:1 compression ratio pairs with high-breathing aluminum cylinder heads. Oil capacity holds 5.0 quarts. Dry long block weight totals 425 lbs.

Key Features of ATK HP20

Restomod builders buy ATK HP20 crate engine base long blocks to obtain potent 347 stroker output while utilizing their preferred intake manifold and fuel induction. The long block drops flush into vintage Ford engine bays using factory motor mounts.

• 3.400-inch stroker crankshaft expands displacement to 347 cubic inches for massive acceleration.
• High-flow aluminum cylinder heads optimize high-RPM airflow while shedding front-end engine mass.
• Performance hydraulic roller camshaft profiles produce aggressive valve lift without excessive valvetrain wear.
• Seasoned cast iron block withstands continuous wide-open throttle stress and high RPM cycles.
• Hypereutectic aluminum pistons maintain close bore clearances under heavy vehicle acceleration.
• External 28-ounce balance specification matches traditional Ford small-block rotating components.
• One-piece rear main seal structure prevents oil weeping past the flywheel flange.
• Balanced ATK HP20 rotating components isolate destructive crankshaft harmonics under load.

Dynamic 347 Stroker Dyno Output

Operating across an energetic 2,500 to 6,000 RPM power band, this aluminum-head 347 stroker produces 410 brake horsepower and 400 lb-ft torque on 91-octane pump gasoline. The performance hydraulic roller camshaft specifies 224 degrees intake duration at 0.050-inch lift with 0.525-inch valve lift. Manifold vacuum measures 15 in-Hg at an 800 RPM curb idle. Hot oil pressure runs between 45 to 65 PSI, keeping crank journals and overhead valvetrain hardware lubricated with pressurized oil during hard street acceleration.

Engine Bay Subframe Fitment Clearances

This Ford Windsor small block uses the classic Ford six-bolt bellhousing pattern, bolting straight to C4, AOD, and Tremec T5 transmissions. External 28-ounce balance requirements mandate matching flywheels or flexplates. Factory motor mount bosses drop into stock Mustang engine bays. The front-sump oil pan clears classic Ford steering linkages and crossmembers without modification.

Break-In Protocol Maintenance Duty Limits

Pre-lube engine oil passages with high-zinc 10W-30 mineral oil using a mechanical primer shaft before initial starter engagement. Fill and bleed coolant through the thermostat housing to eliminate trapped air pockets. This engine package is not engineered for supercharger boost exceeding 6 PSI, continuous RPM past 6,200, or raw marine sea water cooling.

• Drain break-in motor oil after the first 50 road miles.
• Renew synthetic or conventional motor oil every 3,000 miles.
• Inspect ignition timing, spark plugs, and valve adjustment every 12 months.

Warranty Coverage Pallet Crate Manifest

A 12-Month limited warranty protects against material and manufacturing defects. The banded wooden pallet crate houses the base long block, aluminum cylinder heads, stamped steel oil pan, valve covers, timing cover, dyno verification printout, and installation guide. Components ship sealed in protective plastic wrap against oxidation.