While installing the VVT system on a single-cam OHV engine doesn't offer up any adjustability of intake/exhaust overlap timing, it should be noted that simply advancing or retarding the overall valve timing can have significant effects on an engine's powerband, as hot-rodders have known for decades.Typically speaking, advancing the cam timing offers more low-end power, while upper-end performance benefits from retarding camshaft timing.

Although (Billy) 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."

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.