What is correct carburetor?

[new to this]

I am confused - but that is nothing new:banghead

I have two 1966 Birds. One convertible (no A/C) one Landau w A/C.
Neither is emission controlled vehicle. Both are 390 cu.in.

A/C car has Autolite 4100 with 1.12 venturi
Non A/C convertible has Autolite 4100 with 1.08 venturi

Which carburetor is supposed to be on car? Which was changed? I know the 1.08 venturi is 480cfm and the 1.12 is 600cfm.

I know that bigger is not always better - which should I put on?

 

[boaterbob]

The 108 should be the carb for that car and that is the one I would use since it is correct. On the left side of the carb down on the side of the ear it will be stamped so you can figure out what the carbs are for. Go here to find that info.
Ford and Mustang Autolite 4100 carburetors

 

[new to this]

Thanks "boaterbob"

I will definitely keep that link.