First post 1973 1.7, Vacuum troubles? Options

[Hawkiii]

Hi folks. I have been doing searches and just reading posts. Trying to learn as much as possible about these great little cars. I am trying to figure out why mine runs so crappy. The PO told me he rebuilt the engine and put in a mild cam and scrapped the FI and put on the dual Weber’s. From following you guys I am learning that vacuum is pretty important in these engines. I have a friend who was a master mechanic and he has explained many things for me and he stresses that vacuum is pretty important here. So I started checking into the vacuum lines and found I only have one. From one of the carburetors to the vacuum advance on the distributor. Is this correct? I have been trying to find a vacuum diagram for the 1.7 with dual carbs but all the ones I find detail the fuel injection set up. I set up my vacuum tester on the line from the carb to the distributor and started the engine. I could not register any vacuum at all. The needle just twitched at 0. Any help will be greatly appreciated. I feel like I am missing something with only one line. Thanks in advance for your help folks.