GM's 7.0-liter LS7 V8 might best be known in production form as the supercharged heart of the C6 Corvette Z06, but the naturally aspirated base unit has been a very popular crate motor. In a 2008 Hot Rod piece that put eight GM crate motors to test at the drag strip in a 1969 Chevelle SS 396, the 505-horsepower LS7 was only bested by the 640-hp LSX454 and the 720-hp ZZ572, all of which ran in the tens. Since then, ease of use and kindness to tuning has seen the LS7 tapped to power six- and seven-figure supercars like the Falcon F7, Savage Rivale GTS, Ultima GTR, Mazzanti Evantra, and Zenvo ST1. Now Chevrolet Performance has improved the original with the new LS427/570 crate engine, upping output to 570 hp and 540 pound-feet of torque, representing 65-hp and 70-lb-ft increases.
The caveat is that the tech designed to goose the numbers also renders the new crate motor illegal for the street. This is a track weapon only.
The keystone to making this the most powerful naturally-aspirated LS crate engine in Chevy Performance's catalog is a new high-lift roller camshaft, but redesigned internals also include a low-profile intake manifold, new high-rate valve springs, CNC-ported cylinder heads, titanium intake valves, sodium-filled exhaust valves, titanium con-rods, and a 14-inch transmission flywheel from the fifth-generation Camaro Z/28. The Camaro Z/28 also donates its exhaust manifolds, replacing those from the Corvette Z06.
Hot Rod praised the engine's ease of installation with, "The whole deal plugs together like Xmas lights, fires up instantly, and idles like a dream." GM has made the process even simpler, designing a new wet-sump oiling system that eliminates the need for a separate oil tank and oil lines to make it work. There's now an oil pan from GM's F-body cars feeding a specific wet-sump oil pump.
GM didn't reveal a price, but the 505-hp LS7 starts around $11,000 from some retailers, so start looking up from there. The LS427/570 needs a dedicated LS427/570 Engine Controller; the controller for the standard LS7 costs around $1,500, so factor that in, too. The order books are open now.