ATK GM 383 Stroker 525 HP HP107M Stage 2 Mid-Dress LB

Description

Piston ring micro-welding and high-rpm valve float ruin specialty track haulers under extreme transport deadlines. The ATK GM 383 Stroker 525 HP HP107M Stage 2 Mid-Dress LB eliminates mechanical bottlenecks through a high-output commercial long block repower. This 6.3L 8-Cylinder engine develops 525HP, requiring shops to verify sufficient torque converter stall speed before road testing.

Constructed from an ASTM A48 Class 30 iron block, this ATK engine core incorporates competition CNC-profiled A356-T6 aluminum heads and a 4340 forged steel crank. Cold starter draw pulls 180A at 12V. Dry weight is 445 lbs inside 28in length, 26in width, 27in height dimensions with 5.0 quarts oil capacity.

Key Features of ATK HP107M

Restoration facilities buy ATK GM 383 Stroker 525 HP HP107M Stage 2 Mid-Dress LB engines to drop race-grade output into vintage muscle engine bays with zero guesswork. The balanced intake manifold and water pump assembly shorten installation schedules while delivering outstanding volumetric efficiency.

• Stroke length expands to 3.750in across a 4.030in bore to maximize naturally aspirated cylinder fill.
• Mid-dress dressing equips the engine with a high-rise single plane intake and high-volume water pump.
• CNC-ported aluminum cylinder heads flow massive intake volume to sustain peak power past 6000 RPM.
• Forged 4340 steel connecting rods handle extreme inertia forces during manual downshifts.
• HP107M commercial core dynamic balancing prevents destructive harmonic vibrations at high speeds.
• Four-bolt cast iron main caps brace the bottom end against severe combustion chamber pressures.
• Solid-profile hydraulic roller cam lobes ensure aggressive valve lift without valvetrain maintenance.
• High-capacity baffled oil pan prevents pickup cavitation during extreme vehicle launch angles.

Test Bench Dynamometer Certification

Hot bench runs verify power delivery on every HP107M long block engine. Peak power reaches 525HP at 6000 RPM alongside 475 ft-lbs torque at 4400 RPM. Sump oil gallery pressure stabilizes at 60 PSI at 190°F operating temperature. Cylinder compression gauges show 200 PSI across all ports with 3% variance. Crankshaft runout checks at 0.0002in TIR. Dynamic exhaust gas temp stabilizes at 1350°F under maximum dyno torque absorption.

Bay Envelope Maintenance Schedules

Mechanical throttle lever operation needs 6 lbs tension resistance. This high-compression stroker is NOT engineered for stock 87-octane commercial gas, factory cast iron exhaust manifolds, or low-pressure mechanical fuel delivery systems.

• Drain break-in lubricants and renew the oil filter after 500 break-in road miles.
• Verify cold hydraulic roller preload at one-quarter turn past zero lash.
• Retorque intake manifold bolts to 30 ft-lbs after the second thermal cooldown cycle.

Factory Guarantee Crate Inclusions

Manufactured under the strict ATK assembly standard, this stroker engine carries a 2-Year 24,000-mile limited warranty. The heavy wooden crate houses the dressed long block, intake manifold, water pump, valve covers, oil pan with pickup, and an official dyno certification document.