2002 GM Performance Parts Pontiac LSX Trans Am - Department X

As we saw in the last installment of Department X, with its 505-horse LS7 GTO, GM Performance Parts is getting quite aggressive with its crate engine program, particularly with the LS series engines. By offering car builders a very viable alternative to the traditional rebuilding of a worn-out engine or sciencing out a high-horsepower combination, GMPP is putting its engineering assets and expertise in the hands of hobbyists looking for a leading-edge engine combination without the hassle of ironing out all of the bugs.

Dr. Jamie Meyer, GMPP's product integration manager, has been heading up the construction of a variety of project cars for the company, which address the types of installation hassles that both professional and do-it-yourself builders might encounter. The result of this sort of hands-on research has not only been the finished cars, but also the development of support products like the LS series engine controllers that greatly simplify the installation of these high-tech V-8s in just about anything with four wheels.

This time around, we are focusing our attention on the new LSX engines, an extreme-duty, cast-iron version of the LS Series V-8 that offers racers and street machiners the opportunity to build max-effort engine combinations, which can take the punishment of high-rpm, high-boost or nitrous combinations developing up to 2,500 horsepower.

The LSX block was designed by GM, with the help of Pro Stock legend Warren Johnson. "The Professor of Pro Stock" was enlisted to aid the program, as his decades of racing experience offered real-world insight on building strength into the design without adding excessive weight.

This block, while available in bare form for individualized use, is also the basis of the upcoming LSX crate engine. It's a 454 cubic-inch beast, putting out nearly 650 hp, at a price that makes it competitive with the more traditional methods of achieving that power level with a production V-8.

The prototype LSX crate engine is an extremely impressive combination. Displacing 454 cubic inches, the engine uses a 4.185-inch bore with a 4.125-inch stroke. The cast-iron block uses a siamesed cylinder wall design to accommodate the large bore. Additional beefing comes in the way of six head bolts per cylinder (the block still accepts the production 4-bolt configuration) and LS7 steel six-bolt main caps. Reverse-dome Mahle 11:1 pistons are mated to 6-inch Lunati forged steel rods and a Lunati forged steel crank.

Cylinder heads are specific LSX aluminum units. They are very similar in overall design to the LS7 version, but feature an additional row of head bolts for a total of six per cylinder, increasing clamping force and greatly reducing the resistance to head gasket failure due to excessive cylinder pressures.

The castings feature stock LS7 roller rockers (1.8:1 ratio), titanium LS7 intake valves (2.20-inch) and sodium-filled exhaust valves (1.61-inch). These LSX prototype heads flow 360 cfm on the intake at 0.700-inch lift. This is significantly more than even the legendary Ram Air V heads could muster in stock form.

On the induction side is an LS7-sourced composite upper intake manifold with an aluminum base employing the same 90mm throttle body and 40 lb/hr Bosch injectors as the LS7. Ignition chores are handled by the familiar LS-series individual coil pack system.

Crane Cams custom-ground a camshaft with 236/246-degree duration at 0.050, 0.630-inch lift, and a 110-degree lobe separation. With the forged bottom end and rev-happy valvetrain, the LSX 454 can easily withstand a 7,000-rpm redline.