7025150 / 7025151 Front Jet Access:
The 4GC carb on the 65 442's have removable plugs in the front of the bowls to access the jets. The jets can be changed without taking the cover off or removing the carb! (at least in theory) These pics pretty well show it all. It is more than just just the plugs in the housing. Inside the jets are different too. The plugged version has the jet parallel to the plugs, In the non-plugged versions, the jets are angled upward so you can access them straight and square from the top. This appears to be a 65 item only. The factory jet sizes = Primary part number 7002653, secondary 7008681. The last two digits of the part number is the jet size. More info below in the PDF files.