The Six Pack carbs are available separately from Holley under PN 0-4792 for the 350-cfm center carb and PN 0-4790 for the 500-cfm outboard carbs. The center carb has No. 61 jets, a 6.5 power valve, and a 0.031 pump nozzle. The outboard carbs don't have jets, rather a metering plate that controls the delivery of fuel. The plate is the equivalent of a No. 75 jet.