Scirocco Register

I found an unconnected vacume hose on my 83 gti and after consulting the haynes manual i have found it should be for the retard on the the vacume unit on th edistributor. Except my vacume unit only had an advance. My dad tells me that people used to replace the double vacume distributors for singles on old beetles because it improved performance.

Anyone know about this with roccos???

At the moment ive just blocked it up as it wont be helping the crap brakes sucking air.