The engines of yesteryear were pretty simple, with tappets clackity-clacking away on cam lobes, opening valves, and making a ruckus while doing it. Mechanical lifters were adequate for valve operation ...

If we were all die-hard gearheads, we'd all run solid cams. A solid coupling between each cam lobe and pushrod makes the valves move directly in response to the lobe profile. That means the lobes can ...

Editor's note: I met Jack Rhoads in 1967 when his father, James, conceived of a then-revolutionary way to vary valve timing as a function of engine speed. Today the concept is as valid as it was back ...