HOLLEY STANDARD MAIN JET 64 1/4-32 IN THREAD .064 IN HOLE SIZE (PAIR)

These Metering Orifices Control Fuel Flow Into The Metering System. They Are Rated In Flow Capacity Cubic Centimetres Per Minute And Are Changeable For Tuning Purposes. The Shape Of The Entry - Exit And Size Determines Flow. All Holley Main Jets Are Flow Tested And Then Stamped With The Correct Number.