[Ron in Quincy]

The Jets in the Zenith and Holley Carburetors are Millimeter; the only two that require a socket to remove or install are the Cap and Idle jets.

A number of years ago I went to a business that carried Millimeter sizes as well as the standard sizes. Took a Cap and Idle jet with me. A deep well 1/4"
drive 8 millimeter socket fits the Cap jet perfectly; I also got a short 1/4" drive millimeter socket that fit the Idle jet, I ground the end so I could use a small crescent on it. I cannot red the millimeter size as it was where I ground.

For the other Jets I ground a good quality screwdriver to fit the slots so I would not damage the Jets, also narrowed the screwdriver so it would enter the needle driver hole for those carburetors that had a removable needle seat, it also works fine on the Main jet which is installed from the bottom.

Ron