Brake boost vac line

[2Tall]

I have been trying to figure out the right way tie my vacum line for the brake booster on my 71 after converting to dual carbs. I have read on hearing people tapping the manifold or T fit into the cross over tube on kadrons(what I am using).
The question is does it make difference having to reduce the line down to the kadron size. Going from 1/2inch to 1/4 seems like it would impact the function of the vacum. Also any pics of how you made this connection would be helpful. Right now I am looking at having to use more fittings then I want on a vacum line in order to tap into the cross over tube.

 

[rallye dale]

I've drilled and tapped the manifolds on 36 Dell's, done both and am going to tee together

No pics as yet engine not back in

 

[rallye dale]

Don't forget the non return valve aswell

 

[2Tall]

Return valve? Don't think I have seen any other lines to hook up.

 

[ZedBed]

NON-return valve sits in the vac line to prevent backfire in inlet manifold damaging the servo.
You want to stay at at least 10mm dia pipe.

 

[2Tall]

Thanks, If I need to keep the line at 10mm then my idea of "t" tapping the kadron cross over tube will not work.
I am trying to hook this up with out having to tapp the manifolds.