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Hey guys Speedy here
my intake has a single vacuum fitting in the intake, I know I need vacuum for the distributor and is there one for the diverter valve ? I see a straight tube sticking out the side of the carb, is there an inline splitter that connects everything, Ive looked on the net and cant find a diagram........69 390/427 no power brakes
any help is appreciated
Speedy
Last edited by F2 Speedy; Feb 17, 2021 at 05:11 PM.
Besides your single port, they make a dual and a triple port in brass / aluminum that may be better, if your carb will clear.
Well, lets look at all the things that need Vac.
Dizzy
PCV
HVAC
Headlights
Auto Trans
Some Cruise Controls
But not PB on yours.
The dizzy usually feeds off of the front of the carb. (full manifold vac port)
Off the rear of the carb usually goes to PB. So you can use that for a PCV.
The other items can be run off of a plastic "T" . Only the dizzy (and if PB) need a dedicated solo line.
The others can share.
Last edited by HeadsU.P.; Feb 17, 2021 at 07:33 PM.
If you have a Q-jet, the manifold vacuum fitting is the one sticking thru the choke mechanism on the right side of the carb. You can just use a "T" to connect the carb manifold vacuum fitting hose with another vacuum line (other than power brake vacuum feed) and run them to that single manifold outlet fitting.
This car was all in parts when I bought it including the engine, it looks like the front lower middle of the carb was connected to the pcv in the valve cover and I have a larger hose loose on the firewall that connects to all the vacuum canisters and I presume it connected to my single vac fitting in the intake behind the carb, so I could put a T fitting in and connect the distributor and diverter valve to the carb fitting coming out by the choke ?
does this sound right ?
No, that doesn't sound right... The large fitting on the front of the carb base plate DOES connect with PCV valve outlet. That is where the PVC discharge (and the vapor canister discharge, if it is properly connected) get mixed with the intake charge and burned. The large fitting on the rear of the base plate is intended for the power brake booster (if you have P/B). If you do not have P/B, I would recommend just plugging that fitting off. The 'signal' line between the vapor canister and the carb should be connected to a 'timed' or 'ported' vacuum fitting; it should NOT be connected to manifold vacuum. The canister should never purge during engine idle, or poor idle quality will result.
If you have other stock emissions equipment still on your engine, it should be connected as the AIM describes so that it will work as intended.
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Intake manifold vacuum lines
