ATK LS3 GM 415 Stroker 620 HP LS02 Stage 1 Crate Engine

Description

Eliminate tedious custom stroker blueprinting with the ATK LS02 Crate Engine in Stage 1 long block trim. Displacing 415 cubic inches, this GM LS3 stroker produces 620 horsepower at 6,300 RPM and 550 lb-ft torque at 4,900 RPM. Built with a brand-new aluminum block and CNC heads, it equips track cars with lightweight big-inch power.

An all-aluminum GM LS3 block forms the lightweight foundation, reinforced with 6-bolt cross-bolted ductile iron main bearing caps. The rotating kit pairs a 4340 forged steel 4.000-inch stroke crankshaft with 6.125-inch 4340 forged H-beam rods and 10.7:1 forged pistons inside 4.070-inch bores. An internal neutral balance configuration pairs with a performance oil pan holding lubricant reserves under lateral cornering loads.

Key Features of ATK LS02

Road course competitors buy ATK LS02 crate engine assemblies to drop maximum displacement into sports cars without adding front-axle cast iron weight. This long block package fits Corvettes, fifth-generation Camaros, and high-end pro-touring muscle cars.

• CNC-ported LS3 rectangular port aluminum heads maximize airflow volume to feed large 4.070-inch bores.
• 2.165-inch hollow-stem intake valves minimize valvetrain weight to preserve valve control past 6,500 RPM.
• 0.620-inch lift hydraulic roller camshaft profiles maximize valve lift for sudden acceleration off standing launches.
• 238-degree intake duration at 0.050-inch lift profiles the engine for broad mid-range and top-end track acceleration.
• 1.7:1 ratio roller rocker arms stabilize valve actuation without pushrod deflection under high valvetrain stress.
• ATK LS02 stroker components feature dual valve springs with titanium retainers to stop high-RPM valve float.
• Billet double-roller timing set locks in precise camshaft degree alignment across prolonged track events.
• ARP main studs clamp the 6-bolt main caps securely against severe combustion pressure spikes.

Dyno Profile Valvetrain Behavior

Dynamometer calibration tests verify 620 horsepower at 6,300 RPM and 550 lb-ft torque at 4,900 RPM across an effective 3,000 to 6,600 RPM range. The 10.7:1 compression ratio operates safely on 93-octane premium gasoline. Cam duration provides 11 in-Hg manifold vacuum at 850 RPM idle speeds. The internal oil system regulates warm oil pressure between 45 and 65 PSI.

Chassis Clearances Bellhousing Integration

External block dimensions match factory GM LS3 architecture, clearing crossmembers and steering shafts in late-model and vintage chassis. The neutral-balance rear crank flange connects straight to standard LS flexplates or flywheels. Motor mount pads line up with factory LS stands, clearing steering linkages and large-tube headers without chassis cutouts.

Pre-Lube Protocol Service Cautions

Prime internal oil galleries using a dedicated pre-lube pressure tank until fresh lubricant pools around every rocker arm pivot before starting. Use mineral-based 10W-30 break-in oil containing high ZDDP additives to coat bearing surfaces during initial running cycles. This power plant is not engineered for marine bilge setups, forced induction past 6 PSI, or unmetered nitrous shots.

• Replace the initial break-in oil and install a high-flow oil filter after the first 500 operating miles.
• Inspect valve spring seat pressures and check coolant hose clamps every 3,000 miles of street use.
• Check valve lash clearances and inspect harmonic balancer integrity every 12 months or 12,000 miles.

Warranty Terms Shipping Manifest

ATK covers the engine with a 12-Month limited warranty for authorized recreational and street performance vehicle applications. The reinforced crate holds the assembled long block, CNC aluminum cylinder heads, timing cover, oil pan, valve covers, instruction manual, and engine dynamometer report.