LS7 swap by Mark Stielow
Finding Out What It Takes To Stuff An LS7 Crate Motor In An Early Camaro, Dry-Sump And All.A year ago, when we dropped an LS7 into the HOT ROD Solstice, that crate engine was relatively new, and there weren't very many in the hungry hands of the public. But in the time since, GM Performance Parts has sold a bunch of the LS7 crate engines-pretty impressive considering the fairly high street price that hovers around $13,000 (though the list price is $17,000). But the engine (PN 17802397 at your local GMPP dealer) is worth it.

The LS7's parts list reads like a high-end endurance racing engine, with titanium rods and intake valves, CNC-ported heads, offset rockers, and a dry-sump oiling system. With 427 ci and 505 hp out of the box, this is one heck of a package. And as you may have seen in our exclusive dyno test in the Feb. '06 issue, a cam-and-header swap makes it an easy 580hp engine-600 if you want to lean on it. And that's with OE-spec durability. Wow.

As fun as the Solstice project was, we wanted to see what was involved in dropping the engine into a car more representative of the readers of HOT ROD. And what car is more common than a first-gen Camaro? It just so happened that GM Performance Division Engineer Mark Stielow was doing just this swap on his own time: sticking a box-stock LS7 crate motor in his latest Camaro project, a '69 code-named Camaro X. Stielow is known for building first-gen Camaros with wild engines using either oddball cylinder heads or multiple turbochargers, but that was before the LS7 debuted, and now it's a no-brainer for his car. Stielow says, "The goal for Camaro X was to build a fast car, but one that has the driveability and performance of a Z06 Corvette."

Of course, the external architecture of the Gen I (traditional small-block) and Gen III/IV (LS-series) engines is completely different, so it didn't look to be a drop-in engine swap. But thanks to a few parts from American Touring Specialties (ATS), it turned out to be just that. ATS supplied the motor mounts, headers, an oil pan, and a transmission crossmember to allow an F-body T56 six-speed to fit. The company also supplied a hydraulic clutch slave cylinder mount. The engine mounts, oil pan, and transmission mounts made the engine and transmission a bolt-in deal, and the only hole that needed to be cut was for the shifter to come through the floor. The next potential problem area was the dry-sump system, with its plumbing and remote oil tank. Stielow used a Peterson 2-gallon tank and mounted it where the battery used to be.The first step of the swap was to test-fit the accessory drive, headers, and MSD engine-wiring harness. The MSD harness for the MEFI4 engine controller is a true plug-and-play deal. It is terminated for all the stock GM sensors and includes extra sensors and adapters to read fuel pressure at the fuel rail and oil temperature.
With the engine in the car, the next hurdle was figuring out how to make it run-a significant problem considering the LS7's throttle-by-wire arrangement. Adapting a stock wiring harness would be a nightmare, and though GMPD is working on standalone controllers for its line of late-model crate engines (see the sidebar "Controllers to Come"), a unit wasn't available when we were doing this story. Thankfully, MSD has just come out with a killer MEFI4 controller and a mechanical throttle body to allow the engine to work in just about any application. By converting the engine to the MSD EFI system, you no longer need the throttle-by-wire throttle body or the stock mass airflow meter, and MSD's InGenius software allows full control of the system's calibrations. The system comes with an engine calibration that will start and run the engine, but for the best performance (especially if you've thrown in a different cam and/or added headers), you should fine-tune it to the application.

The fuel system consists of a bolt-in stainless fuel tank from Rick's Hot Rod Shop and an in-tank Walbro pump. The LS7 uses a returnless fuel system, so the stock Corvette regulator (PN 10299146) is mounted back by the tank and sends 58 psi of fuel pressure to the stock LS7 injectors. The last thing to button up was the exhaust system, which consists of ATS's stainless steel tri-Y headers and a Stainless Works 3-inch exhaust system, installed by Stenod Performance.

So how does it run? Well, it's wintertime in Detroit (where the car is) as we write this, so Stielow doesn't have any numbers on it yet. But, he says, "Based on the power and weight compared to my other cars, it should run 11.90s at about 120 mph." As with every Stielow-built car, that performance should come on stiff, road-racey suspension and low-profile tires. You could certainly build an 11-second car much cheaper with a traditional small-block and a carburetor, but you'd be hard pressed to match the driveability, mileage, and durability of the LS7 crate engine.

Controllers To ComeWhen this engine swap was happening, GM Performance Parts didn't have an EFI controller for the LS-series crate engines, but it does now. PN 19166567 is a new GMPP plug-and-play controller for the LS7 (PN 19166568 for the LS2). Unlike the MSD controllers, these are nonprogrammable units, meaning they come with the factory tune for the production engine. GMPP is looking into releasing programmable units for the entire LS crate-engine family, but the company doesn't have them yet. For more information on the GMPP controller, check out page 298 of the current 2007 catalog or log on to www.gmperformanceparts.com.