Chevrolet Performance L8T 6.6L Long Block


  • 401 hp @ 5,200 rpm/464 lb.-ft. @ 4,000 rpm
  • Largest Displacement LT-Family Engine
  • Forged Steel Crankshaft
  • Must Use with 6L80 Transmission

Shipping is free, but there is a delivery fee for residential addresses.

L8T Chevrolet Performance Long Block

P/N 19433748

401 hp @ 5,200 rpm / 464 lb.-ft. @ 4,000 rpm

L8T 6.6L Tech Specs:
Part Number: 19433748
Engine Type: Gen V Small Block C-8 direct injection spark ignition
Displacement (cu in): 400 (6.6L)
Bore x Stroke (in): 4.060 x 3.860 (103.25mm x 98mm)
Block (P/N 12619171): Cast iron with 6-bolt nodular main bearing caps
Crankshaft: Forged Steel
Connecting Rods: Forged powdered 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): 193° intake / 199° exhaust
Cylinder Heads (P/N 12703610): Aluminum, rectangular port D/I with 59.02cc chambers
Valve Size (in): 2.130″ intake / 1.590″ exhaust
Compression ratio: 10.8:1 (nominal)
Rocker Arms (P/N 12619829): Investment-cast, roller trunnion
Rocker Arm Ratio: 1.81:1
Fuel Delivery: High-pressure direct injection (2,175 psi/150 bar)
Recommended Fuel: 87 octane
Ignition System: Coil-on-plug
Maximum Recommended RPM: 5600
Reluctor Wheel: 58x
Balanced: Internal

Installation Notes:

  • Engines 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.
  • Use Front End Accessory Drive system P/N 19433745 for applications with air conditioning and Front End Accessory Drive system P/N 19433746 for applications without air conditioning
  • Includes 8-bolt flexplate for automatic transmissions
  • Used with Engine Control kit 19433736 (must use 6L80 transmission). Includes programmed controller, wire harness, pedal, oxygen sensors and mounts, MAF, Fuel Line Pressure Sensor, and Fuel Pump Power Module (FPPM).


Weight 425 lbs

L8T Chevrolet Performance Long Block

19433748 Chevrolet Long Block

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.

Chevrolet Performance Crate Engines include a 24-month or 50,000-mile (80,000 kilometer) limited warranty.

Click here for more detailed warranty information.


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Prop65WARNING: These auto parts can expose you to chemicals including phthalates and lead. Installing or using these parts can expose you to other parts containing these chemicals and to engine exhaust, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to

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