Triple groove valves are intended to allow the valve to rotate with in the retainer. Primarily, this help prevent carbon build up in the head. For a street car, this can help the car run smoothly, longer. But the most important thing in racing and high RPM is that the triple groove locks do not clamp the valve. So if the valve tends to float and there is impact against the seat, the impact will be transmitted to the lower of the three grooves, the thinnest and weakest part of the valve, with greater chances of failure.

A single groove valve, on the other hand, allows the keepers or locks to tightly “ clamp” the valve below and above the groove, and the groove is mostly there for location of the keeper, absorbing just a fraction of the load and impact. It allows for more contact surface area which leads to less friction. For high horsepower, high rpm engines this is the best choice.