Single carb manifold

To the side of the manifold by the base there are two spigots, one goes up to the carb with a hose on , the other one is larger in diameter and mine has a short length of hose with a bolt in the end to blank it off. Where should this really go? I only know this because the bolt had come out which meant I was getting uneven running and backfires.
Yes I am a dimbo

 

Brake servo vacuum feed.

 

So is it ok to be blanked off? Popester

 

Yes, blank it off

 

Thanks Paul, just read that servo's were an option which the first owner clearly didnt take on.

 

Or it goes to the stock air cleaner via the thermo switch to operate the hot air flap in the air intake ..
Its where mine went.