Solid brass CNC machining, accurate size, good coaxiality Clear and tough texture, Ensure that it is very strong after insertion into the carburetor cavity Single order contains 8 bushings Suitable for most 3/8 carburetor throttle shafts Brass Bushing Dimensions: Outside diameter 11mm (7/16) Inside diameter 9.52mm (3/8) The carburetor model for this bushings:GM TBIs Carter Thermoquads Holley 4-barrels (including muscle car carbs) Ford (Autolite) carburetors and more Please check if the size of the damper shaft matches the product before purchase! How to use the bushings:1 Remove the throttle shaft, clean the carburetor damper blades and throttle shaft 2 Using a hand-held variable speed drill (recommended bit size is 10.5mm, smaller than the actual aluminum hole 0.1mm), drill the aluminum hole of the carburetor throttle shaft 3 Reaming operation using the 7/16" reamer included 4 Insert the front of the brass bushing into the aluminum hole 5 then pass the throttle shaft through the brass bushing