I put 800 miles on a new Silverado with the 6.0 engine so it was time to dump the factory fill. After reading all the pros and cons on new engine break-in I decided to go to GC with the first oil change. I picked up 12 qts at my local AZ, they seem to still have plenty, and made the change. There was a definite change in the sound of the engine under the hood. It was like throwing a blanket over the motor. I will be searching the AZ to build up my stash. I hope they continue to make this stuff.