New competition valve cotter for early heads with the large single groove valve, these are precision CNC machined from 4340 and heat treated to a better spec than EN24T and claimed to be stronger in fatigue life. These locate better in the valves and make it easier to control spring heights. Made to RACE specification for performance heads or valves by going one better in quality and fitment, do not take a risk--buy the best available on this part. These are sold as individual halves you need 16 for a car. We also carry the stock valve keepers if you're on a budget.