ATK HP411PM GM 489 Stroker 565 HP Stage 2 Performance Crate Engine

Description

Haul heavy enclosed car trailers using the ATK HP411PM Crate Engine in Stage 2 performance mid-dress form. This 489 cubic inch big block Chevrolet produces 565 horsepower at 5,400 RPM and 590 lb-ft torque at 4,200 RPM. Arriving with intake manifold and water pump, it offers builders complete control over their fuel and ignition setup.

Engine block architecture centers on a heavy 4-bolt main cast iron block finish-honed with deck plates for optimal ring seal. Inside, an internal-balance rotating kit pairs a 4340 forged steel 4.250-inch crankshaft with 4340 forged H-beam rods and 10.0:1 forged pistons. Cylinder bore measures 4.280 inches, supported by a 6-quart steel oil pan to manage oil reserves under acceleration.

Key Features of ATK HP411PM

Performance enthusiasts buy ATK HP411PM crate engine packages to drop high-torque big-block performance into project cars without sourcing separate short blocks. This mid-dress configuration repowers muscle cars, pro-street machines, and vintage Chevrolet hauling trucks with immense power.

• High-flow dual-plane aluminum intake manifold comes torqued in place to eliminate intake runner vacuum leaks under load.
• Aluminum cylinder heads with high-flow rectangular intake runners drop overall front-end vehicle weight while maximizing flow speed.
• 2.25-inch intake and 1.88-inch exhaust valves pass massive air volumes to clear exhaust gases without backpressure bottlenecks.
• 0.547-inch lift hydraulic roller camshaft produces huge low-end torque while eliminating traditional flat-tappet camshaft wear.
• 230-degree intake duration at 0.050-inch lift ensures brutal power delivery throughout the entire 2,800 to 5,800 RPM band.
• 1.7:1 ratio aluminum roller rockers prevent valve guide wear and maintain precise valve lift at continuous high RPM.
• ATK HP411PM mid-dress hardware includes a cast iron water pump with factory big-block belt pulley dimensions.
• 4340 forged steel H-beam connecting rods withstand high cylinder pressures without rod beam deflection under load.

Dyno Calibration Performance Spectrum

Dyno testing confirms 565 horsepower at 5,400 RPM, backed by 590 lb-ft torque at 4,200 RPM. This 489 stroker operates on 91 or 93-octane pump gasoline without pre-ignition. Idle vacuum registers 12 in-Hg at 900 RPM, maintaining support for standard brake assist systems. Hot operating oil pressure settles firmly between 50 and 70 PSI across the RPM range.

Chassis Bounds Bellhousing Drops

Exterior dimensions follow classic big block Chevrolet lines, dropping between frame rails on factory A-body, F-body, and C10 chassis. The internally balanced crank flange mates with standard zero-balance flexplates or flywheels for TH400 or manual transmissions. Motor mount points align with GM factory frame pads, clearing mechanical steering shafts and tubular headers.

Priming Directives Operating Boundaries

Spin the internal oil pump with an external drive tool until fresh oil coats all rocker arms before initiating starter rotation. Use 10W-30 conventional break-in lubricant with high zinc additives to safeguard moving surfaces. This engine is not engineered for marine salt water use, supercharged applications above 8 PSI, or multi-stage nitrous systems.

• Change the initial break-in engine oil and replace the spin-on oil filter after the first 500 street miles.
• Inspect intake manifold hold-down bolts and check coolant hose clamps every 3,000 miles of street use.
• Test valvetrain lash adjustment and check harmonic balancer keyway integrity every 12 months or 12,000 miles.

Warranty Statement Physical Manifest

ATK provides a 24-Month or 50,000-Mile factory warranty for authorized street performance applications. The heavy shipping crate contains the assembled big block engine, aluminum intake manifold, cast iron water pump, harmonic balancer, oil pan, valve covers, instruction manual, and official dynamometer sheet.