These Butterflies are finely detailed showing the cross shaft and screws holes for each butterfly disc.
Although they are made to fit Mark Johnson's Enderle injector hat, they measure .215" diameter and may fit your application. Click here to see the Mark Johnson's BBC.
Just drill out your openings, insert a cross shaft that connects the throttle linkage and barrel valve and install these butterflies on the shaft.
Contains three nickel silver butterfly discs, .215" diameter, 1/16 scale.