Just thought I'd share my solution to the vacuum connections on bike carbs, didn't want multiple pipes, y pieces and a smoothing vessel.
The steel tube, should provide smoothing as well as connecting the seperate runners.....

Oops better post the pic
Rescued attachment DSCN0858.JPG

Been there done it etc
then dump it
sorry but i could not get it to work
i must say it was not exactley like yours.
4 pipes in a tank 1 out to the dizzy + i tryed one way valves aswell
good luck with what you are trying let us know how you get on
Graham

[Edited on 3/3/08 by jacko]

looks just like mine

seems to work but not been far in it yet

dave