1968 Mustang (and Ford) Vacuum Diagrams
170 and 200 with Imco and auto trans, without AC
170 with Thermactor and manual trans
200 with Thermactor and manual trans
289 2V and 302 2V with Imco and auto trans, without AC
289 2V and 302 2V with Imco, auto trans, and AC
302 4V with Imco, auto trans, and AC
289 and 302 with Thermactor, manual trans, and AC
390 2V Premium Fuel with Imco, auto trans, and AC
390 2V with Imco, auto trans, and AC
390GT with Thermactor and auto trans, without AC
390GT with Thermactor, manual trans, and AC
427 with Thermactor and auto trans

"Imco" is special emissions tuning, "IMproved COmbustion"
"Thermactor" is Ford smog pump