I have a 1977 GMC K10 that I need a vacuum hose diagram for. The Haynes manual doesn't have anything unfortunately.

Does anyone know where I can find such a diagram? I'm trying to figure out which hoses go to what in order to prep for an emissions check.

Try looking in a Chiltons manual, sometimes the diagrams they have are better.

maybe find a buddy with nearly same truck if you can't find an AUTOZADVANAPAREILLY store near you to get a chiltons or haynes from. either that or move