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L8T Long Block

L8T Long Block

SKU: 19433750

Heavy-Duty Power from Chevy’s HD Trucks

With 401 horsepower and 464 lb.-ft. of torque on tap, the L8T crate engine is the largest-displacement LT-family engine in our lineup, offering plenty of low-rpm torque. Direct injection offers more precise fuel control than port injection, enabling a comparatively high compression ratio of 10.8:1 in the engine, which contributes to its high output.

It’s built with a forged steel crankshaft and other high-strength parts. Additional features such as oil-spray cooling for the pistons and a cast iron, long-skirt cylinder block with six-bolt, cross-bolted main caps contribute to the engine’s strength and durability. Comes with production style exhaust manifolds.

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.


  • Horsepower

    401 HP


  • Torque

    464 LB-FT

  • Tech Specs

    Part Number: 19433748

    Engine Type: Gen V Small Block V-8 direct injection spark ignition

    Displacement (cu in): 400 (6.6L)

    Bore x Stroke (in / mm): 4.060 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 (nominal)

    Rocker Arms (P/N 12619829): Investment cast roller trunnion

    Rocker Arm Ratio: 1.8:1

    Intake manifold (P/N 12639087): Composite

    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

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