Air cleaner base and trumpets connection to carburetors

[BlackJag]

There are four holes on each of the three SU carburetors on my Series II OTS.

The bottom two holes take the hex screws, lock washers and nuts to connect the air cleaner's base and trumpets part to the carburetors.

What, if anything, goes into the other two holes indicated with red arrows on my photo?

If nothing goes into these holes, what is their purpose other than letting in unfiltered air into the carburetors?

[mgcjag]

Dashpot chamber vents......Steve

[BlackJag]

Thanks Steve. I didn't have a clue, but totally understand now.

[bitsobrits]

That they are open to atmosphere is why one should remove the dashpots and thoroughly clean them and the air pistons at least every other year. If the car is driven frequently then once a year is not too often.