The Delbruck Performance Series Carburetor Calibration Kits include an assortment of metering rods and jets. One pair of metering rod retaining springs and a complete assortment of step-up springs is included with this calibration kit. Includes an assortment of metering rods and jets Includes one pair of metering rod retaining springs Comes with complete assortment of step-up springs Components and quantities are specifically tailored for each carburetor It offers more volume with optional single or dual inlet for total fuel plumbing flexibility