Vacuum lines

[Sus-stato]

Hi
I own a wk Holden supercharged and my engine is idling rough, moving up and down between 600 and 1000 revs.
And the car hesitates when under heavy load.

I had a look at the lines and saw the elbow connection is cracked bad, I looked around auto stores and know one housed the part.

Does anyone know where to get the part and where the line goes to?



Thanks