I searched around and found a place you can get the wiring diagrams and repair information you need. It also covers all the '60 -'80's vehicles.
Go Here Vintage Repair Manuals and Select Category that covers the vehicle you need vintage repair information for. This was the only place I found that covered your '60's - 80's. At present the information is FREE.
VINTAGE – The new Vintage Repair Center contains “vehicle specific” repair information from the mid – 1960s to 1982. Almost all Domestic and Import cars, light trucks, and vans are included. Categories of detailed text, tables, and diagrams include: Engine Mechanical, Chassis, Electrical, Wiring Diagrams and Engine Performance.
More Coverage Than Anybody
this is much cheaper than trying to buy all the paper manuals and trying to keep track of them.