"ducts" on secondary baffle plate

[novadude]

I've noticed a lot of OE Chevy carbs have a little duct or "box" welded to one side of the secondary baffle plate that fits around the secondary discharge nozzle.  These are always on the side that would be the top-level of a dual plane intake.  I assume this is to direct the fuel towards the front of the manifold, since there is less plenum depth for the air/fuel to straighten out before making the sharp turn into the runners. 

Were these "ducts" effective or not?  Any reason to use (or not use) a secondary baffle with the welded on duct in a dual plane application?

Thanks!

[Cliff Ruggles]

I've built carbs with and without the baffled dividers and to date can't really see any difference anyplace using one with the baffle.  The baffle will also provide a stop for the airflaps if you convert a later truck carburetor to the front pull-off style, so it's nice to have a few around.....Cliff