The arms are tightened to 18 ft-lb. Because of the hydraulic design of the camshaft and valvetrain, no further adjustment is required-just torque 'em down and they're done. | 
Re-installing the valve covers is the final step in the rocker arm swap. Easy, huh? | 
While the engine cover is still off the engine, the thermostat is replaced with this lower-temperature, 160 unit. |
To ensure the trailblazer's ls2 engine controller doesn't freak out at the detection of the new rocker arms and lower-temp thermostat, the performancepac includes a diablosport Predator ii handheld tuner with a custom, pre-programmed tune from SLP. It uploads simply via the interior's diagnostic port. | 
Despite its relatively large dimensions, the crossmembers, frame sections, and spare tire leave precious little space under the trailblazer to route a dual-exit exhaust system, which is why the factory system is a single-outlet design and why SLP has to work with a factory Y-pipe and single muffler before splitting the exhaust into dual outlets. The project vehicle in this photo also wears a set of prototype long-tube headers (see sidebar story) and high-flow cats. | 
Here's another view of where the Y-pipe meets the cat-back system. Note the tight fit around the frame crossmember and vehicle floor. There's not a lot of extra room to work with here. |
From the Y-pipe connection (at bottom), the s SLP stainless muffler mounts in the stock location, with the stock hangers, but has two outlets instead of the stock system's single outlet. | 
Interestingly, the stock exhaust outlet is the one that wraps around the spare tire and heads out to the passenger side of the rear bumper. SLP's dual-outlet system adds a seemingly straighter path to the driver side. | 
Here's a bottom-up view of the exhaust system's routing to the bumper. It looks so natural, we wonder why chevy didn't do it in the first place. |