ATK GM 383 TBI Stroker 320 HP HP05 Stage 1 Long Block

Description

Low-end hesitation and cylinder bore wash shorten commercial route delivery cycles in older utility vans. The ATK GM 383 TBI Stroker 320 HP HP05 Stage 1 Long Block restores heavy hauling capabilities through a precision industrial engine rebuild. This 6.3L 8-Cylinder build makes 320HP, but shops must upgrade fuel pump volume to feed higher stroker displacement.

Poured from ASTM A48 Class 30 gray iron, this ATK engine core mounts high-swirl iron heads and a nodular iron 3.750in stroke crank. Starter draw requires 170A on 12V systems. Dry engine mass equals 460 lbs, featuring exterior block dimensions of 28in length, 26in width, 27in height. Crankcase fluid capacity requires 5.0 quarts of high-grade motor oil.

Key Features of ATK HP05

Fleet mechanics buy ATK GM 383 TBI Stroker 320 HP HP05 Stage 1 Long Block configurations to achieve massive pulling power without redesigning factory fuel management wiring. The dedicated cam profile preserves manifold vacuum so stock computer sensors read throttle transitions accurately.

• Increased 383ci stroker displacement develops exceptional low-RPM torque for commercial hauling.
• Swirl-port cast iron cylinder heads accelerate intake charge speed for crisp off-idle throttle response.
• Hydraulic flat tappet camshaft grind works within stock electronic control module fuel curves.
• Heavy-duty hypereutectic pistons withstand thermal shock from protracted stop-and-go driving routes.
• HP05 commercial core clearances guarantee high oil pressure even during prolonged summer idle periods.
• One-piece Viton rear main seal stops chronic crankcase leakage onto vehicle bellhousing plates.
• High-tensile rod bolts resist fatigue under sudden deceleration and downshift braking loads.

Shop Cell Dynamometer Metrics

Dyno testing validates every HP05 long block engine prior to warehouse departure. Output attains 320HP at 4400 RPM while twist reaches 400 ft-lbs torque at 3200 RPM. Hot idle oil gallery pressure registers 45 PSI, rising to 60 PSI at operating speed under 195°F temperatures. Individual cylinder compression verifies 175 PSI with variance under 4%. Crankshaft runout checks at 0.0003in TIR. Exhaust gas temp peaks at 1240°F under dyno loading.

Vehicle Constraints Tuning Protocols

Throttle cable pull operates with 5 lbs return resistance. This low-RPM stroker is NOT suited for racing applications above 5000 RPM, carbureted marine setups, or late-model multi-port fuel injected passenger sedans.

• Flush break-in engine oil alongside the oil filter element after 500 miles of vehicle service.
• Preload hydraulic lifters to one-quarter turn past zero lash during initial cold valvetrain setup.
• Confirm intake manifold bolt torque at 35 ft-lbs following initial operating temperature warmups.

Warranty Statement Shipping Hardware

Built to meet the verified ATK assembly standard, this durable unit features a 2-Year 24,000-mile commercial warranty. Each shipping crate contains the assembled long block engine, oil pan, valve covers, timing cover, internal oil pump assembly, and validated dyno test document sheet.