the reason was they had one in stock at mr. fiat 100 miles from me. i paid more for it but didn't have to wait for international shipping

I just purchased a 123 distributor for my '72 S2 1,3S. This distributor (Lancia-4-R-V) has a metal tube on the side of it where one would connect a vacuum advance hose. The original distributor doesn't have a vacuum advance hose leading to it. So my question is what do i do with this tube? Attach a ...