Do pre 1967 Mopars have a ported vac advance port on carb, or did they just use manifold vacuun for the Vac advance. Thank you.

should be ported.

No mopar had manifold ported vacuum for distributor...wait for it..

What does this statement even mean?

I think he's waiting for a typical moparts argument to break out? I'm interested in the answer as well, I'm not old enough to remember when or if direct manifold vacuum was used. I_think_ported vaccuum started in the emissions era but don't really know.

Ported vacuum comes from a small opening / passage that is slightly above the primary throttle blades at normal idle opening IE: 750 or so RPM with no radical camshafts that require more throttle opening at idle speeds.

As the throttle blades begin opening during acceleration the air passing by the opening begins drawing air (vacuum if sealed of hooked up to a non leaking vacuum advance. This is known as the venturi effect. See pic below. the red indicates air flow, the blue vacuum. As the throttle blades are opened, more air passes by the port and the vacuum increases adding more advance.
So there is no vacuum available at idle speeds .


Manifold vacuum ion the other hand is highest when the throttle blades are closed ( depending on camshaft) as the pistons are trying to draw air/ fuel against a restricted opening (the throttle blades). However it drops rapidly on acceleration due to the throttle blades opening. As one reaches cruising speed and the blade opening in relaxed the vacuum then returns to a higher state.
Which is better? I'm not going to open that debate.
To my knowledge Chrysler used ported vacuum in most applications. That may have changed during the emission years. hope this helps

I started working in service stations in 1961, I remember a lot of the early GM cars had manifold vacuum advance back then, hence the disconnect the vacuum advance and plug the fitting instructions before setting the timing
As far as I can remember now all Mopars engines I worked on had ported vacuum advance, all of them

I know what ported vacuum is I just could not understand the comment as written, even if trying to be sarcastic. I do not know for all cars, but the Carter AFB pre emission were ported. I do believe that all Chrysler were like that as they had a different approach for emission/CAP for their cars at least in the 60 and early 70. So ported was not an emission thing. Chrysler chose to use vacuum advance to control timing on load, and chose to have idle run with no vacuum advance.

In the true cap years starting in 66 for Chrysler CA only. And 68 for all states, they did use the Vacuum canister for 4 speed cars to switch to Manifold vacuum during deacceleration only. Cars were tuned for lean idle and retarded ignition. Even the hemi starting in 68.

The info Cab furnished jibed with what I'd gleaned over the years. It seemed the older guys, the chev centric guys, all asserted manifold vacuum was the "correct" way to hook up vacuum advance to the point they'd arbitrarily change it to manifold on whatever car they were working on even if it didn't come that way. By the time I started my mechanic years (1973) mid '60's cars coming into the shop was a bit of a rarity, let alone earlier ones. At that time cars 5~10 years old made up the bulk of junkyard denizens which made parts for my '68 readily available cheaply.

Well my 51 Plymouth has ported vacuum stock

He is not asking which is best, just how did they come originally. So there really should be no debate, Chrysler used ported.

Were they still using hard plumbed lines then or had they gone to rubber hoses by then?

I think they where steel up to much later in the mid 1960, maybe even later

Hard line from carb to vacuum canister, as is the 52 Dodge 230 I bought to build and hot rod.

i'm not going to start a debate here. everything was ported up to around 74ish [?], then, if i REMEMBER correctly [???] there were trees on the rear of the intake manifold that went to a vacuum "enhancer", then to a temperature sensor in the water pump housing, then to the carb, then to the distributor and vacuum pots controlling the air filter snorkel flaps.
i just looked at a 440 out of a 78 newyorker, and a 400 from a 76 newport [both with thermoquads] that are on my shelf, and that is the way they have the myriad of vacuum hoses ran. they were this way when removed, and i just left everything as was just to keep the holes plugged.
i "think" this started in 74, because i remember the round multi-port "vacuum enhancer" on the china wall of my wife's 74 charger with a 400/727 combo.
remember, this is for the big blocks. i don't remember, nor have, any small blocks to compare.
so manifold through temperature [wax pellet] senders to ported.
i don't know what this setup could be correctly categorized.

Short answer is yes there is a ported vacuum connection on carbs before 67. I have a 62 383-2bbl, and a 62 413-4bbl both have it done in rubber hoses. 1960 413-4bbl has it with a hard steel line.

The OP specifically asked about pre 67. Why bring up the newer stuff?

because it was stated previously that there was never manifold vacuum used.
your point could also be used about 30's and 40's engines, as well as the steel and rubber lines.
i was just offering a little more to the story, sorry if i rubbed you the wrong way.
please accept my apology.

Wait for all the know it alls (keyboard jockeys) to claim otherwise.

Not for distributor advance