"The installation of a a CV carburetor with Custom air cleaner on a Panhead, Shovelhead or Ironhead Sportster involves two problems:

• the protruding upper carb end interferes with the commonly flat backing plates of accessory air cleaners
• omission of the stock CV air cleaner results in an unsupported carburetor

This smart kit inludes a 3 mm spacer plate, which resolves the first problem and a flange adapter with two spiral springs to connect spacer and plate and thus safely hold the carburetor in its rubber flange = resolution of the second problem.
Will fit all motors with 2-bolt Tillotson, Bendix or Keihin (butterfly) manifolds. Installation also requires a 2-bolt flange adapter and a carburetor support bracket, which both need to be purchased separately."