For my A/C project I need to attach a vacuum line, is the area circled in white a good location to pull vacuum? What is the item circled in red? Should something be attached to yellow area or what is it for?
The port on carb is filtered air pickup for choke(feeds from inside air cleaner, no vacuum here)... The device in red is the EGR valve, was originally had ported vacuum connected, most were disconnected shortly after the cars were driven off the dealer's lot... The feed to the transmission modulator valve is a good source, depending on fitting you may have to T off it...
One of the very first things I always do on these old motors is to remove all the emissions junk and get rid of the same "emissions junk related spark curve". Easier to work on too. The fuel and ignition curves MUST be re-tuned to take full advantage of and maximize air/fuel ratios for better power, economy, and also gives you a cooler running engine. Red circle is the carb spacer with EGR valve.. makes these old cast iron manifolds run hotter than they already do. The port below the air cleaner is not a true vacuum source and only serves to free-breathe or "lightly pull" residual crankcase gasses from the engine under heavy/WOT conditions. This only serves any useful purpose when the PCV valves affect has dropped away completely when manifold vacuum falls off. EDIT: Krazy Comet treed me again.
These links may help also: http://www.1bad6t.com/Maverick/repair/emission_controls_02.html http://www.1bad6t.com/Maverick/repair/emission_controls_04.html
Should port on carb have a filter or some hose attached to it? Can I just remove EGR and install block off plate? Is modulator only vacuum line that runs to transmission?
Normally there is a rubber line on the carb that connects to a steel tubing that fits into a port on exhaust manifold... There is also a second steel tube that connects back to carb the draws the hot air for the thermostatic choke(see link, scroll down to illustration of 2bbl carb)... These lines fit into rear of passenger side exhaust manifold, often rust out and get tossed... It isn't hard to form new lines if yours are missing... http://www.1bad6t.com/Maverick/repair/fuel_system_05.html
