My heating and AC system is seriously trashed. On the vacuum modulator, htere is only one line and Im pretty sure theres suposed to be two. The one that is there is cut after about two feet. Second, on the passenger side, coming out of the wiring sleeve, there is another vacuum line that isn't hooked up to anything. Basically, tell me where all the lines are supposed to be and what to connect them to. What can I use to replace the damaged ones? Also, what is manifold vacuum? I've been told I have to hook one of them up to a source of manifold vacuum. Sorry for this being so long and thanks in advance.

 

Anyone? Its really hot and Im dying without AC and Im gonna be real cold in January with no heat. Please help.

 

I'm gonna assume you have a carb on that 383. Manifold vacuum is just vacuum from a port on the carb. You run pcv to the larger port on the front of the carb, and depending on what your car is equipped with accessories to the smaller one(s). If you have cruise, then there will be a line for that. The line on your pass side engine bay is probably for the heater diverter valve since you have a/c. Hope this helps.

 

A bit more precise, but intake vacuum is a port on the carb (or intake) that always has vacuum on it when the engine is running, as opposed to only when the TB's are opening (ported vacuum).