need some mechanical info on VW dual carbs

[GhostRider]

I'm trying to list a pair of Weber dual carburetors for a buddy of mine that go to a old VW Bug/porche, the only part numbers I can find on them is 3012L and 3012R. Now I know the L and R is left and right but can't find out what the size of the carbs are. They made them in 34mm, 40mm, 44mm and 48mm, how do I measure them to tell size, cant find out anything in the computer any help would be greatly appreciated. thanks

[Zundfolge]

Are the 3012L and R numbers on the air cleaner bases and not the carbs? I'm thinking that's the part numbers of the air cleaner assemblies. Here's a set of those for sale.

The size and model number of the carb should be stamped on the body near where it bolts to the intake manifold.

Here's an example I found http://imageshack.us/f/68/WeberIDF_2.jpg/

[GhostRider]

got him to take another look and it is just as you said, the number was faint but there on the base, thanks Zundfolge