[Purdy Swoft]

Sharp edges on the head of the valves is an indication that the valves have been ground, many times and not necessarily an indication that they are original!!! Like Tom says, they can cause preigmition and will burn quickly. It is best to never use a valve with ground sharp edges on any engine... I would avoid valves that are magnetic because they will burn in a few thousand miles and causer a low speed miss or worse ...