The C5 paces the Indy 500...
The C5 paces the Indy 500 in 1998 and a replica is offered to the public. For those that want to get noticed, this gets the job done with the Radar Blue paint, wild graphics, and bright yellow wheels. Not too many were built or sold, so resale value is strong here.
Key notables for the LS1 include a switch to a more powerful PCM in 1999 which is more tuner-friendly for you computer hackers out there. In 2001, they then received the freer-breathing LS6 intake manifold and the LQ4 camshaft for a total of 350 horsepower. The 2001-2004 ZO6s all had great heads, cams, and engine/drivetrain packages, making them the most desirable and as expected, the most expensive. Over time the 5.7-liter LS1s and LS6s have proven to be incredibly reliable, efficient, and powerful. The main thing to look for is weak oil pressure on early LS1s and signs of abuse, which typically show up as oil leaks and odd engine noises. These cars hardly ever spew a drop of lubricant but dances with the rev limiter, missed shifts, and general lack of LSX respect will also result in piston slap on cold start and lifter noise. Documented maintenance records help, while frequent oil changes with quality synthetic lubes promote engine life.
Don't be scared of modifications such as long-tube headers, a mild cam and some tuning as these mods are pretty much considered bolt-ons and won't greatly affect the life of the car. Once you get into superchargers and nitrous, things change. We'd recommend asking a good technician to see the quality of the work that is on a prospective car that you're looking at. LSX engines can easily handle a moderate boost in power with a power adder but elevated power levels, no matter how sexy they may sound on paper, require a careful eye to catch potential problems.
Driveline
The rest of the C5's mechanicals are equally unique in design and engineering. The transmission, mounted directly to the rear transaxle, sits behind the driver to offer near-perfect weight distribution and thanks to a close-ratio T56 with two overdrive ratios and a 3.42 ring and pinion, taking advantage of the LS1's broad powerband is just a slick shift away. Automatic versions received a four-speed automatic with a single overdrive gear and either 2.73 or 3.15 final drive ratios.
T56 transmissions can become rough shifting over time, but it does not mean the car was abused. Because the C5 uses such a long input shaft within its torque tube, the synchronizers are asked to do a lot more than a regular car as it has to match the heavy input shaft speed to the selected gear's speed. Some cars have been completely cured by the use of GM's Synchromesh fluid while other cars with over 75,000 miles may need a transmission rebuild.
Automatic models with the 4L60E generally last until 100,000 miles without a problem so long as it is serviced with fresh fluids over its life. Be cautious of cars that have been fitted with aftermarket torque converters and/or have been programmed via the PCM to remove the torque management feature, which normally limits power in between shifts. Generally, transmission life can be cut in half (or more) if these modifications have been made together.
Rear differentials can sustain 500 horsepower all day long and failure is relatively low, even when modified. Gear swaps are not exactly cheap, so make sure a gear change is what's best for your engine combination before making the commitment. Generally, the 3.42s work best for mild application but 3.90s and 4.10s love high-revving naturally-aspirated engines in front. When you approach the 600-rwhp level, consider a hardened shaft upgrade and even a transaxle brace kit.
 The LS1 had only a few changes...  The LS1 had only a few changes since its 1997 debut in the Y-body. A switch to a returnless-type fuel system in 1999 (shown) kept horsepower at 345 while the fitment of an LS6 intake manifold and some internal upgrades in 2001 upped power to 350. |  The LS6 arrives in the 2001...  The LS6 arrives in the 2001 ZO6 with 385 horsepower. This technical update centers around new 243 casting cylinder heads with slightly larger valves, a lumpier cam inside a revised block with better crankcase air management, and a new intake manifold. Red engine covers were the only outward cues that let anyone know what you had underneath. |  In 2002, the LS6 was revised...  In 2002, the LS6 was revised again, this time cranking out 405 horsepower thanks to an even larger cam, new intake valves, and more aggressive mapping. The rest of the engine and the ZO6 that it lived in was mostly carried over. Guys were running 12.0s with these cars bone-stock. |
 The center glovebox is not...  The center glovebox is not that useful, despite what this GM photo makes you think. I mean, come on, who has the four-tape collection of Duran Duran in their car? About the only thing accurate here is space for the cell phone. Consider an aftermarket storage solution to be high on your list, as well as a nice cupholder to get rid of that sad excuse of one that Chevy gave you. |  The rear cargo area on the...  The rear cargo area on the coupes is quite useful. Underneath the rear compartment lids are a large storage well in center and two smaller ones to the side. The removable roof panel snaps into place back here but if the rubber mounts get worn out, it can rattle when you drive. On convertible and FRC/ZO6 models, the trunk is more abbreviated, but just as useful. |  C5 coupes, as mentioned earlier,...  C5 coupes, as mentioned earlier, come with a removable roof section that comes off easily. Note the condition of the rubber seals, especially on the sides where they meet the rear bulkhead as they are known for wind and water leaks. The tinted acrylic roof panels are known to crack internally over time, making them look faded and worn pretty quickly so factor in several hundred bucks to get it properly restored. Since the C5 was designed to be an open top car from the get go, there is no need to worry about heavy cowl shake or a sloppy ride. |