Is this possible

[SvMinor]

Ive been looking to get an Su carb with the Extra breather attached,but I was wondering if it is possible to drill and tap a Pipe into an existing Su Carb,cancelling the need to change the manifold,

If it is possible,What size Drill ,Tap and Die would I need,Also any recommendation on what pipe to use?

[bmcecosse]

I suppose you could! But really - is this worth it? These later carbs are often almost 'given away' on ebay!

[MarkyB]

I was thinking along the same lines but looking at the insulating block that goes between carb and manifold.
The effect should be as good, just a question of how to tap it and fit a pipe in that would be strong enough to stand up to the vibration.
Also I'd be very nervous drilling into a carb.

[bmcecosse]

Good idea MB! I would say don't go bigger than a 1/8" hole - maybe start with something smaller. the one on the carb is 'deactivated' at idle - which the plastic one would not be - but it still works well - I did similar - but using the servo connection on a Mini manifold.

[M25VAN]

You can get a carb spacer that already has a vacuum take off built in which would save any drilling. I don't know how well drilling into the carb would work. On the late carb the entry tube narrows down to a pretty small hole inside the carb. Maybe you would lose vacuum by having a larger hole entering into the carb system?