I go between 10,000 and 12,000 miles on mine. I have used Amsoil since around 80,000. I send a sample in to be tested every time. 254,000 miles and going strong.

Aaron

68 Roadrunner 383/AT
69 Dart GT Conv. 383/AT
05 Dodge Ram 4x4 Cummins
06 GoManGo R/T Daytona #757
68 Coronet 440