15. To top off our engine, we went with Holley’s new Ultra Street Avenger carburetor (PN 86779HB, $549). At 770 cfm, it’s sized just right for our mill, and the electric choke will make it easy to live with on the street. The carb features ultra-lightweight aluminum construction along with billet metering blocks and base for more strength than cast pieces. It’s also easy to adjust and change the spring for the vacuum actuated secondaries.