HP01-42 Genuine Holley Carburettor Main Jets - Size 42 PAIR [122-42]

These main jets control fuel flow into the metering system. They are rated in flow capacity "cubic centimeters per minute" and are changeable for tuning purposes. All Holley Main jets are flow tested and then stamped with the correct number.

Features:

- Fits All Holley Model 2010, 2300, 4010, 4011, 4150, 4160 & 4500

- 1/4-32 thread

- Standard main jet

- Genuine Holley product