Rochester 4GC
Rochester QuadraJet
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Most came with square-bore 4GC carbs, but a few came with spreadbore Rochester Quadra-jets.  Some had PCV valves.  These two items are found only on late build '65 442s. Carburetor datatag numbers  are ( Air conditioned 7025151 )   ( Non-Air Conditioned 7025150 ) The only functional difference appears to be the presence of a "hot idle compensator valve" on the 7025151 model.
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.
Without Front Access
With Front Access
The two pictures below show the inside differences between the two styles.  The picture on the left shows that the jets can be changed by removing the plugs and accessing them from the front and the picture on the right shows the angle allowing for top access only.
Metering_Jets_Rods.pdf
Metering_Jets_Rods.pdf
1965_Olds_Carb_Info.pdf
1965_Olds_Carb_Info.pdf
http://www.carburetorfactory.com
http://www.carburetorfactory.com