Where do i find a vaccum line diagram for a 1980 ford f150

Two places come to mind. Underneath the hood, there should be an emission-control diagram for your vehicle, on a sticker from the factory. This will show proper routing of emission control vaccuum lines. The second place would be a factory shop manual/Haynes manual. If you have any mechanic friends, they can print something like this out for you from Alldata.

try auto zones help site for repairs