On my car (originally a v6, now a carbed v8) i have two lines coming out of the firewall. One short with a 90 fitting and one long with a straight fitting. Where do these hook up? Do they both go straight to the carb? Do they go to the Vac canister underneath on the front drivers side? Thanks guys.

 

What color stripe is on each of the vacuum lines?

 

Vader's diagram is missing one of your 2 lines. It's a year-dependent thing. Evidently his service manual is from a different year than your car.

Your 2 lines should be purple, and white. The diagram only shows the purple one.

The purple one goes to the vacuum canister/accumulator, and supplies vacuum to the system. The canister should have 2 ports; the one line plugs into the smaller one, and the larger one should have a hose going from it to the intake somewhere to get vacuum.

The white one goes to the heater control valve. That's the one that's missing on that particular diagram. You don't necessarily have to use that, since (as you can see from Vader's service manual page) alot of cars didn't come with them anyway.

 

well as far as I can tell my lines have no stripe. just black. The only lines I have come out of the firewall into the engine bay right behind the passenger side valve cover. One is about 8 inches long (with the 90) the other is about 2 feet long. Other than that the only vaccum lines in the entire engine compartment are the ones I installed for the advance and brake booster, and pc valve. So where does mine install? Do they both go to the vac canister and then one from there to the carb?

 

The 90* one is part of the main vacuum system that supplies vacuum to the HVAC controls under the dash. It should plug into a vacuum check-valve that prevents the vacuum from bleeding off when you shut off the engine or go to WOT.

The original system went something roughly like this, if memory serves:

Full manifold vacuum source on engine intake to a fairly large vacuum line (7/32") to a vacuum "T" with check valve inside. The T is shaped like a cone. The vacuum line from the engine plugs into the nipple on the tip of the cone. Off the back of the cone are 2 more vacuum nipples, smaller in diameter (or maybe there's a single nipple on the back with a T directly behind it- difficult to remember). One you plug in your 90* fitting, the other is a vacuum line over to the vacuum reservoir in the driver's side fender.

Your other vacuum line is, like sofakingdom said, to drive your heater core diverter control valve, which you may or may not even have on your new motor (it's ceretainly not required that you use one, but many 3rd gens had one). It doesn't need to be hooked to any vacuum source. It SUPPLIES vacuum to the heater control valve when called for by the HVAC controls. If you don't have a heater control valve just plug this line and tuck it away.