The GM Atlas series of engines presented the world with GM's very refreshed view of the straight-six engine. Released in 2002 as the 4.2L Vortec, it took engineers and the automotive press by storm. It may be one of the most efficient truck I6 engines ever made, and it competes handily against other companies V8 offerings. It does, however, remain somewhat in the shadow of the GM LS & Vortec V8 engines.

As the Atlas engineering and tooling is modular from their inception, it has a five and four-cylinder siblings, the 3700 and 2800, respectively. These engines all share the same bellhousing bolt pattern with each other. However, individuals swapping these into Jeeps should understand that they do not share the same 90-degree Chevrolet V6, V8, I6, Iron Duke bolt pattern. The Atlas family can marry to a 4L60E auto with the appropriate bellhousing, as well as the GM AR5 transmission for the I4 & I5 versions. Engine mount availability is not yet there. Computer and wiring support is very good, as with the other GM engines.

- The Novak Guide to Installing GM Engines into Jeep Vehicles