i have a 74 164 that i have just fitted tripple carbs to, was going to run a vacuum line from the manifold for the brake booster but have bought a 12v vacuum pump instead, there is a vacuum hose going through the firewall also, is this only for the heater controls or has it anything to do with the aircond controls as well? will upgrade the aircond to a sandon type comp while im at it, if its only for the heater i may bypass it as i can live without it in qld. thanks for any help.