If we made a list of the most...
If we made a list of the most misunderstood components in your LS-series performance motor, chances are the camshaft would be right at the top.
While enthusiasts can comprehend the fact that the camshaft is responsible for opening and closing the intake and exhaust valves on an LS motor, relating these events to crank position, engine displacement, or even operating speed is somewhat more difficult. The difficulty is only compounded when you add things like forced induction to the mix. From an anatomical standpoint, the camshaft can be likened to the brain, as the cam profile determines how effectively (when and where) breathing takes place. Camshafts are one of the major determining components of the effective operating range of the motor. Of course, the cam timing must be combined with the proper intake manifold, head flow, and primary length on the exhaust for optimum operation over a given rpm range, but the right cam all but determines the character, or personality, of the motor. Stock or ultra-mild aftermarket cams will provide a dead-smooth idle while more radical grinds can transform that mild-mannered motor into one seriously radical ride. Unfortunately, that radical ride route often includes ill-tempered, cantankerous behavior until the motor comes on the cam, but such is the price for all that high-rpm heaven. As luck would have it, modern cam technology has come a long way since the introduction of the original small-block Chevy. Technology has provided not only a much more efficient small-block in the form of the new LS family, but it has also allowed us to produce impressive power, driveabiliy, and even fuel mileage all in one package.
Many LS1/LS2 and LS3 enthusiasts at least understand the basics of cam timing. They realize that so-called "Saturday-Night Special" grinds are much wilder and potentially more powerful than the production cam profiles. The problem arises when deciding to choose between these two extremes, especially for a daily driver. The temptation is certainly there to go "BIG" on the cam profile, after all, isn't bigger always better? The problem with going big is twofold. The first problem is that the cam profile must be selected not just for bragging rights at the drive-in (or coffee house), but rather to work with your existing components. Adding the right cam to your otherwise stock motor can result in impressive power gains. Adding wild cam timing to your otherwise stock motor will likely result in a drop in power throughout most of the rev range and can actually decrease peak power since the cam was designed to run effectively at 7,500 rpm and the rest of your stock components (intake runner length, head, and stock valvesprings) sign off at just 6,000 rpm (or less). As a general rule, the closer to stock the remainder of the components, the milder the cam profiles that should be chosen. This means leave those weekend-warrior cams to the drag racers and stick with mild but effective profiles that will offer power gains not just at high rpm, but through the entire rev range. After all, what good is it to add 25 hp at the power peak only to loose 35 lb-ft down at 3,000 rpm? Think for a moment about where (what rpm) you spend most of your time driving and choose a cam accordingly!
 Our test motor started out...  Our test motor started out life as a 6.0L truck block. Nothing fancy here, just your average 4-inch bore LS combination. |  The 6.0L truck block was stuffed...  The 6.0L truck block was stuffed with a 4-inch stroker crank, forged rods and pistons to produce a finished displacement of 408 cubic inches. The dished pistons worked with the AFR heads to produce a street- (and later boost-) friendly static compression ratio right near 10.0:1. |  Originally, our motor was...  Originally, our motor was to be used to compare a pair of cams (one hydraulic and one solid), but since the test mule was already equipped with a Comp XR277HR XFI RPM hydraulic roller, we decided to include that in the test as well. |
 Before our test, the 6.0L...  Before our test, the 6.0L stroker was topped of with a set of AFR 205 Mongoose heads. The copper head gaskets were used during the later testing with a large single turbo. |  The 205cc intake ports offered...  The 205cc intake ports offered exceptional peak and average airflow numbers. With peak flow nearing the magical 300 cfm, what really makes these heads offer so much power is the all-important average airflow. |  The exhaust flow was equally...  The exhaust flow was equally impressive, with peak numbers reaching 230 cfm. Even down at just .400-inch lift, exhaust flow exceeded 200 cfm. |