For those readers who may be unaware, the naturally aspirated 6.6L V8 L8T is the same powerplant cradled by gasoline-powered variants of the Chevy Silverado HD and GMC Sierra HD heavy duty pickups, and now, the L8T is the largest-displacement LT-family engine on offer from Chevrolet Performance. Peak output is rated at 401 horsepower at 5,200 rpm and 464 pound-feet of torque at 4,000 rpm, but unsurprisingly, the V8 also packs in loads of low-end torque along the way. Maximum recommended engine speed is 5,600 rpm.
In terms of construction, the L8T block is made from cast iron and incorporates six-bolt nodular main bearing caps, while the crankshaft is made from forged steel. The connecting rods are made from forged powder-metal, while the pistons are made from hypereutectic aluminum. Compression ratio is set at 10.8:1.
Further features include oil-spray cooling for the pistons and production-style exhaust manifolds. The L8T crate engine package also includes the throttle body, oil pan, PCV tube, evap tube, oil dipstick, oil fill tube, and cap, as well as a high-pressure direct-injection fuel pump pre-installed. However, it does not include the controller, harness, oxygen sensors, or Front End Accessory Drive system. Alternatively, customers can opt for the L8T Long Block option, which includes the direction injection cylinder heads, coil-on-plug ignition, oil pan, and dip stick, but does not include the intake manifold, throttle body, fuel pump, or fuel injectors.
In terms of transmission options, the 6.6L V8 L8T crate engine is available to connect to the SuperMatic 6L80-E six-speed automatic, with customers offered a few options for the torque converter, including a 2400 – 2800 stall, and a 3000 – 3400 stall. Further related parts and accessories include an accessory drive system, both with and without air conditioning, and the L8T controller kit required to run the L8T crate engine with the 6L80 automatic transmission.