The "Governor" is a four-hole aluminum spacer with tapered inserts which may be quickly changed after removing the carburetor. Restricts air/fuel entry and reduces power slightly to prevent wheel spin. Inserts range in size from 1. 000" to 1. 400" for custom tailoring for quicker lap times. Fits all Holley 4 bbl. 4150/4160 series carburetors.Pit Stop USA offers Allstar Performance "The Governor" Adjustable 1" Aluminum Carburetor Spacer ALL26180 at low everyday prices. Be sure to check out all of our products from Allstar Performance including Allstar Performance Carburetor Spacers.