2002 GM Performance Parts Pontiac LSX Trans Am - Department X

The power numbers are very exciting: 641 horsepower at 6,400 rpm, with 610 lb-ft of torque at 4,900. Equally impressive is the flat torque curve-at 3,000 rpm, the LSX is making 520 lb-ft of axle-snapping grunt. "The great thing about these engines is that they have the breathing capacity to make big power at high rpm, but are large enough to have plenty of low- and mid-range torque," Dr. Meyer explains. "This is a great combination, and it's ready to bolt in."

Indeed, that kind of power, along with its 7,000 rpm redline, will ensure exhilarating performance in just about anything the engine is mounted in. Best of all, it has a fairly docile demeanor on the street.

The Trans AM Project Car
The recipient of this prototype LSX engine is an '01 Trans Am convertible that was originally used by the Firebird Brand Team as a mule car for the '02 Collector Edition Trans Am. Like the LS7 GTO featured last month, the T/A was selected for the LSX installation, as it is anticipated that the engine will frequently be swapped into Fourth-Gen F-Bodies.

This swap actually was easier than the LS7 conversion in the GTO, as this version of the LSX uses a more conventional oiling system, so the overall packaging was very close to the production LS1 the T/A was originally born with. Exhaust gases flow through a set of Stainless Works headers with 1.875-inch primaries and 3-inch collectors to a 3-inch DynoMax system.

From there, power is transferred on to a 4L85-E automatic transmission. For those not familiar, it's a beefed-up and electronically controlled version of the 4L80-E that is based on the tried and true Turbo 400 automatic. Getting this transmission into the Trans Am was a difficult procedure, as the floorpan required some modification to accept the tranny's large case. "We used a really big hammer," Dr. Meyer jokes.

From there, the power is then delivered to the stock rearend. Obviously, the third member is not really up to the task of harnessing that level of power, though it has done alright so far. As long as slicks are not used, it will probably be fine, though we expect a 12-bolt upgrade in the near future. Braking power is upgraded with a quartet of drilled Brembo 11.9-inch front and 12-inch rear disc brakes.

On The Road
Due to a transmission calibration issue, we were not able to drive the LSX Trans Am, but did have a brief ride in it before the photos were taken. The engine was truly spectacular and the exhaust note was intoxicating. After experiencing a few seconds at full throttle, I can say that when properly calibrated, this car would be deep in the 11s.

As one would expect, the unleashing of 600+ horsepower on a convertible F-body has introduced a wealth of creaks and rattles. Though many might take issue with it as "noise, vibration and harshness," it really adds to its developmental mule personality. It's a rough-and-tumble street machine and it means business.

Though we were a bit disappointed by our all-too-brief encounter, Dr. Meyer gave us an alternative. He offered to let us drive a '96 Impala SS with the same driveline. Though it was substantially heavier than the Trans Am convertible, the car was completely sorted out and ready to roll.

The plan was for me to drive it to the track and from there I would get a chance to wring it out. Upon getting in the Impy and settling in, Dr. Meyer cautioned me and said, "Now I know that you've driven some really fast cars before, but be careful, this car is a rocket." I nodded, turned the key and the engine roared to life-and I mean roared. Even though the LSX was identical to the one in the Trans Am, it seemed louder-perhaps the perception of such a radical engine in such a luxurious car was more of a contradiction to my senses.