LQ4

[Editor’s Note: Because the LQ4 and LQ9 engines are so similar, we’ve combined them for this engine upgrade guide, which is part of a series of LS engine upgrade guides assembled by a team of LS experts at Summit Racing that we are sharing at OnAllCylinders. For a primer on the entire LS engine universe, read LS Engines 101:

Mechanically similar, General Motors’ LS and LS-based Vortec engines wound up on almost every branch of the GM family tree: Chevy, Pontiac, GMC, Cadillac, Buick—heck, even Saab, Hummer, and Isuzu got some LS love. Since LS and Vortec engines are so common, they’ve become the go-to performance and swap engines of the modern era. These motors are