Although Godbold returned to this subject, it quickly became obvious that he had other ideas aching to burst out of his mind. Ideas that can be summed up in the initials VVT-that's variable valve timing to you and me. "The L92 truck motor is incredibly impressive, making 400 SAE corrected horsepower stock and 430 hp with headers," he began. "With one of our cams and the phaser limiter kit, we made 500 hp, and it did not lose power anywhere. It's a great cylinder head, then you add the variable valve timing. We start out by giving the smaller cams lots of advance, up to 10 degrees, then you can retard those about 16 degrees. With the larger cams, piston to valve is tighter on the intake so we go down to 5 degrees advance. These designs run best with a sweep curve of about 12-degree retard, which helps the engine carry at high rpm."

The whole thing is better. You can move the cam around in the motor. Say you do a NASCAR cam with a 110 LSA. You can run it at 102, 106, 110, and 114 centerlines and get an idea of how it responds. It may fill in a gap, 104, 108...look at torque curve...102 best torque, 114 best high-end power. Good teams look at the specific track, look at where the engine spends time. This is something that would have taken us a lot of time and four guys on the dyno, and analyzing data in the past. Then, after you do it, you have to compromise. With the cam phaser, you can advance or retard the cam centerline to the position it runs best at each rpm. That's cool, really cool. You can get a 60-plus horsepower gain, with no loss anywhere. You can have control of the cam timing by tweaking a curve in your ECU, just like typical electronic ignition timing. It's like going from points to coil-on-plug.

Read more: http://www.superchevy.com/how-to/eng...#ixzz3CaEQeq92