ATK GM 383 Stroker 500HP HP55 Stage 1 Aluminum Head Engine

Description

Premature valve guide wear and crank flex sideline high-output specialty utility vehicles. The ATK GM 383 Stroker 500HP HP55 Stage 1 Aluminum Head Engine resolves high-load powertrain failures through a commercial long block repower. This 6.3L 8-Cylinder package generates 500HP, requiring mechanics to verify adequate high-octane fuel flow to support higher compression ratios.

Constructed from an ASTM A48 Class 30 gray iron block, this ATK engine core includes competition-grade A356-T6 aluminum heads and a 4340 forged steel crank. Cold starter draw pulls 175A on 12V. Dry weight is 440 lbs with dimensions of 28in length, 26in width, 27in height holding 5.0 quarts oil.

Key Features of ATK HP55

Specialty fleet shops buy ATK GM 383 Stroker 500HP HP55 Stage 1 Aluminum Head engines to deploy serious naturally aspirated output without expensive custom race shop delays. Upgraded valvetrain hardware and precision CNC chamber profiles support high-rpm stability under severe duty cycles.

• Optimized 383ci stroker configuration produces exceptional cylinder pressure across broad power ranges.
• High-flow CNC-ported aluminum heads facilitate complete exhaust scavenge during high-rpm operation.
• Aggressive hydraulic roller camshaft profile generates 500HP without requiring solid lifter adjustments.
• Forged 4340 steel H-beam connecting rods handle extreme tensile stress during downshift engine braking.
• HP55 commercial core architecture features four-bolt main caps to resist crank flex under heavy acceleration.
• Forged aluminum dome pistons provide high thermal tolerance against cylinder detonation events.
• Premium dual valve springs prevent valve float during sudden mechanical gear shifts.
• One-piece Viton rear seal eliminates bellhousing oil seepage during prolonged operational use.

Bench Dynamometer Load Statistics

Rigorous test protocols measure performance on each HP55 long block engine prior to crate delivery. Peak power attains 500HP at 5800 RPM alongside 480 ft-lbs torque at 4200 RPM. Sump oil gallery pressure registers 60 PSI hot at 190°F fluid temperature. Compression gauges show 195 PSI across all cylinders with 3% variance. Crankshaft runout checks at 0.0002in TIR. Dynamic exhaust gas temp measures 1350°F under maximum dynamometer resistance.

Vehicle Constraints Maintenance Intervals

Mechanical throttle lever operation demands 6 lbs pull resistance. This high-output engine is NOT engineered for original factory low-pressure mechanical fuel pumps, standard 87-octane fuel, or computer-controlled vehicles requiring integrated emissions modules.

• Perform full break-in oil and filter changes following the first 500 miles of service.
• Confirm valvetrain adjustment cold, setting lifters one-quarter turn past zero lash.
• Verify cylinder head bolt torque down to 70 ft-lbs after the initial thermal cycle.

Commercial Protection Included Hardware

Manufactured under the rigorous ATK assembly standard, this stroker engine carries a 2-Year 24,000-mile limited warranty. The wooden freight crate contains the long block assembly, aluminum valve covers, oil pan, timing cover, oil pump with pickup, and signed dyno certificate sheet.