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Horsepower: 401 HP

Torque: 464 LB-FT

Heavy-Duty Power from Chevy's HD Trucks

In addition to the complete L8T crate engine Chevrolet Performance offers the L8T Long Block — the high-output, direct-injected foundation of the Gen V Small-Block-based 6.6L engine offered in the Silverado 2500HD and 3500HD models.

Our L8T Long Block includes the direct injection cylinder heads and coil-on-plug ignition system, as well as the oil pan with dipstick, but does not include the intake manifold, throttle body, engine-mounted high-pressure direct injection fuel pump or fuel injectors. All must be sourced separately to complete the engine assembly. Additionally, the Front End Accessory Drive system is not included. See Installation Notes for recommendations.

INSTALLATION NOTES

• Engine is shipped with high-pressure direct-injection fuel pump installed
• Front End Accessory Drive system must be ordered separately and includes hydraulic power steering, with center pulley. Pulley-mounted fan not recommended. 
• Includes 8-bolt flexplate for automatic transmissions
• 2024+ use with Engine Control kit 19435726 for 6L80-E transmission. Use Engine Control kit 19435606 for 10L90-E transmission. 
• Available in Connect & Cruise with 6L80 and 10L90 transmission options

TECH SPECS

• Part Number: 19435733 (2024+)
• Engine Type: Gen V Small Block V-8 direct injection spark ignition
• Displacement (cu in): 400 (6.6L)
• Bore x Stroke (in / mm): 4.065 x 3.860 (103.25 mm x 98 mm)
• Block (P/N 19420904): Cast iron with 6-bolt nodular main bearing caps
• Crankshaft (P/N 12708884): Forged steel
• Connecting Rods (P/N 12675746): Forged powder-metal
• Pistons (P/N 12699527-R, 12699529-L): Hypereutectic aluminum
• Camshaft Type (P/N 12672469): Billet steel hydraulic roller
• Valve Lift (in): 0.500 intake / 0.492 exhaust
• Camshaft Duration (@ 0.050 in): 193º intake / 199º exhaust
• Cylinder Heads (P/N 12703610): Aluminum rectangular port D/I with 59.02cc chambers
• Valve Size (in): 2.130 hollow intake / 1.590 inconel exhaust
• Compression Ratio: 10.8:1
• Rocker Arms (P/N 12619829): Investment cast roller trunnion
• Rocker Arm Ratio: 1.8:1
• Intake manifold (P/N 12639087): Composite
• Throttle body (P/N 12730580): 87mm diameter (single-bore)
• Fuel delivery: High-pressure direct injection (2,175 psi / 150 bar)
• Recommended Fuel: 87 octane
• Ignition system: Coil-on-plug
• Maximum Recommended RPM: 5600 rpm
• Reluctor wheel: 58X
• Balanced: Internal