6. Over the course of the day, jets were changed in the carb 10 times. Holley supplied us with one of its jet kits, giving almost all the jets we needed. I say almost because only two jets are supplied in each size. Many times you’ll run the same numbers front and rear, and with only two of each size jet, you have to go up or down one size. We went up, making the mixture just a touch richer.