Rochester Quadrajet primary metering rods are used to tailor primary part throttle air/fuel enrichment . Fits most 1975 and later non-electronic Rochester Quadrajet carburetors, except some truck and marine carburetors that use the early style rods. Dimension stamped in rod indicates maximum diameter of taper.

Quantity: 2 Primary Metering Rods for Rochester Quadrajet carburetors.

Rod Specifications:
Cruise diameter: .052"
Power tip diameter:.036"
Rod overall length: 2.395" - 2.400"
Does NOT fit Quadrajets with Electronic Mixture Control Solenoid (MCS)

Primary Rod Tech:
A 52M rod has a large diameter of .052" and a small diameter "power tip" of .036". The .052" section of the rod is positioned in the metering jet during light throttle driving. During heavy acceleration, manifold vacuum decreases allowing the power piston to rise positioning the small diameter (.036") power tip in the metering jet.
Larger diameter rods will lean part throttle/cruise air fuel mixtures. All "M" primary metering rods have the same small diameter power tip (.036"). A great way to fine tune your Q-Jet for better driveablity and fuel mileage.