Hello all thanks for taking the time to read! I have a 77 ranchero gt with the 400 in it. The guy before me has put a edelbrock sp2p manifold with a motocraft 4350 (D5AE RA). Don't know if this matters but he put a flow master exhaust on it too. I can get it to start but the idle is out of this world high! I have been monkeying around but can't seem to figure it out. I believe something has to be wrong with the vacuum lines. Any help is appreciated thanks a million! Side note. Is this set up any good or should I just spring for a different carb/manifold set up?
Since the idle is high and he just installed a new carb-intake combo, I would suspect a leak from the intake or carb. You can take a can of WD 40 or other type of cleaner with the straw and start the engine. Plug all vacume lines including the one going to the brake booster. Spray around the intake first where it bolts to the heads and block and listen for any change in rpm's. If nothing then go to the carb. Spray around the base. The manifold is ok for a daily driver but I would go with a different carb. Greg
#1 needs to be connected to manifold vacuum. Does #6 go over to your distributor? If so, there should be NO vacuum present at idle. Either 5 or 6 (don't know which one) should have manifold vacuum at one, and ported vacuum at the other. Ported only shows vacuum when the throttle blades are opened, and should not have any vacuum when blades are closed. The ported one should be connected to your distributor, and the other you can use for #1. The rest (2,3, +4) you can leave open for now.
2 is the fresh air supply to 3, which draws hot air through the choke stove (below 3, in the manifold). 4 is the bowl vent for the EVAP charcoal canister. 5 and manifold vacuum are *supposed* to go to what's called a thermal vacuum switch, with three ports, for the distributor advance. When the engine's cold, it gives you ported vacuum for better engine cranking, then once hot, it switches to manifold vacuum for the longer advance. 6 is what's called 'venturi vacuum,' and is connected to the EGR valve through another TVS that has only 2 ports instead of three. That way, the EGR won't operate until the engine's past a certain temp.
