The Lexus LFA is powered by a 72-degree bank angle 4.8-liter V10 engine equipped with dual VVT-i carrying the 1LR-GUE designation with a maximum output of 412 kW (560 PS) delivered at 8,700 rpm. Its maximum torque output of 480 N·m (354 lb·ft) arrives at 6,800 rpm, 90 percent of which is available from 3,700 rpm. The engine redlines at 9,000 rpm, but with a fuel cutoff set at 9,500 rpm, and is constructed using forged aluminum pistons, forged titanium connecting rods, and solid titanium valves. The V angle of the LFA's V-10 engine is set to 72-degrees (as opposed to the 90-degree V angle present in a Dodge Viper's V-10) to fully balance the firing force from the pistons. This 72-degree angle allows for even firing from the pistons without the use of a split-journal crankshaft, thus improving engine efficiency as well as lowering overall weight. Dry sump lubrication prevents engine oil starvation through high speed corners and lowers the engine's center of mass. Air is fed directly from beneath the hood through a visible slit passing into a dual stage variable intake manifold and then into ten individual throttle bodies before finally exiting from a dual stage titanium muffler.
The LFA's engineers selected a V10 engine over an equivalent displacement V8 engine for its ability to rev higher, and over a V12 for its lower reciprocating mass, allowing for more rapid engine response. Lexus claims their engine can rev from idle to its redline in 0.6 seconds and an analog tachometer needle could not accurately track the LFA's changes in engine speeds. This necessitated the use of a digital tachometer which can instantly display engine speed. The engine reportedly weighs less than the manufacturer's own 3.5-liter 2GR-FE V6 engine. Engineers attempted to make the engine sound like that of a Formula One car with high revs, while at the same time maintaining reliability and vibration control. Along with other manufacturers such as Ferrari, Toyota had produced their own F1 engines and chassis designs. The exhaust note has been described by Toyota engineers as the "roar of an angel", and a US television spot later used the engine sound to shatter a champagne glass via resonance frequency.
The powerplant gives the LFA a power-to-weight ratio of 5.9 lb/hp and enables it to reach a top speed of around 325 km/h (202 mph). Like the IS F Yamaha co-developed the engine cylinder heads. The engine exceeds Euro V emissions. The engine is installed with a front mid-engine placement. According to Chief Engineer Haruhiko Tanahashi a front engine layout was selected instead of a mid engine layout as it is inherently more forgiving dynamically, affording less experienced drivers a wider safety net.