CARB Help---Rochester 2 barell

While looking at tri-power setup and stock modified tri-power setup me and the pops have noticed that on some Rochester 2g center carbs bases that there is a little port hole/ vacuum hole. It is below the ****erflies rite in the indention corner on the p***enger side rear bolt hole. I had looked a t few extra ones I have and three had it and one did not.

I quess my question is what is this hole for? It is definately ****ing vac***. I can not seem to find a happy medium on my carbs but when we spray carb cleaner in this hole the motor gets real smooth which indicates that this vacuum is a culprit to one of my problems. I JB welded it up last night to seal it but out of curiosity we want to know from a carb guru or somoene that may know what exactly this hole is for. I mean it is straight dirty infiltered vauum into the base of your carbs. Cant seem to good for it.

Any help is greatly appreciated, Thanks Rusty

 

dizzy advance? I can never remember if you are supposed to run it off of the carb or the intake. So if thats way wrong don't listen to me!!

 

This is a very small pin hole type hole in the base. It is designed to have nothing hooked up to it, but for what reason this is what i am trying to find out.

 

Can't say I'm an expert on all things 2-Jet but this is what I observed.
I just looked at one I have on the shelf and it has that hole in BOTH sides and they are above the throttle plate at idle.
probably have to do with mid range mix.
They might just be for a particular application where the carb was too rich at just off idle so they quick fixed it?

Drill the epoxy back out or plug th other side too because you're carb's out of balance now.

 

anyone else know whats up with this hole? I've got a carb with the hole in it and its just on the one side. doesn't seem to make much sense.