This LS4-Swapped Saturn Is the Very Definition of ‘Sleeper’

This little commuter is really a monster sleeper hiding in plain sight.

Few people will ever remember Saturn S-Series as anything but plastic-bodied appliances that General Motors built in the 1990s and early 2000s. The cars never had anything resembling a tuning culture and few people ever raced them. They earned their reputation as basic and cheap transportation. And if you saw the red Saturn SL1 with black body cladding by LS1Tech member Sean R, you probably wouldn’t think twice about it. Little would you suspect that its stock hood hides a 400-horsepower LS4 swap that makes it one of the most unsuspecting sleepers you’ll ever find.

The engine came from a 2006 Chevy Impala SS, one of the few cars given the 5.3-liter, transverse-mounted LS4 engine. Using the bellhousing from a 60-degree GM V6, Sean fitted that to a Getrag five-speed to make a manually shifted monster. He has broken one axle, which he had sleeved to make the custom fit until he could have nice axles made for it, but the replacements have run fine. Don’t believe it? Sean has ample video proof of this real, working, absolutely wonderful thing that he’s made.

The mods list is relatively short: stock 243 heads, an LS9 valvetrain, and a Professional Products Typhoon intake manifold. The custom-built dual exhaust does have some tight clearances, including skirting the oil pan, but it does all run under the body. To preserve the stock appearance, Sean has also dumped the exhausts mostly out of sight.

From the videos he’s posted of the car, it seems relatively quiet, although the LS4’s bark is enough to let the observe know it’s not quite a single-cam Saturn engine under the hood. There’s a tinge of “Why?” in a project like this, but Sean answered that question in the project’s introductory post: “I’m honestly not sure what possessed me to want to do such a crazy project.” Some things defy reason, but we’re glad he’s taken no half measures with the LS-swapped SL.

The real kicker is obviously how stock it looks with a fitting hood and small (at least for now) wheels. The tachometer even works. We’re pretty sure the average street-machine driver will be looking for the source of the fading roar long after the Saturn has disappeared from view with only a few whisps of tire smoke as a clue.

Sleeper? You’re doing it right. Check out the full  LS1Tech thread here.