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Mojoe9955

Mojoe9955

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I bought this Demon with a 6 cyl. It has a Holley 2 barrel on it and it runs, albeit not very well, but I'd like to correct that. I don't have a service
manual so I have a couple question?
What is this fitting on the intake...it doesn't look properly set up to me... what is it for? I'm missing PCV valve and the distributor advance is not hooked up, are these supposed to be routed to this as well? Do I even need this with the Holley set up?
Thanks

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You can download a free service manual @ mymopar.com
 
What year is the car? The fitting is a temp sensor, for either emisions, or lean burn. Don't worry about it. Just leave it as a plug in the hole. The carb is not correct for any Mopar. It is either a aftermarket Holley 350 cfm, or 500 cfm (need the numbers on the air horn). Or it could be from a Ford (not likely). You do need to hook up the PCV system, and the distributer advance to the ported vacuum port on the carb. Also, check for any vac leaks. Start with that.
The large hose from the manifold vacuum tree, that goes toward the carb. What is it connected to? Also the small hose from the vac tree, looks to be going to the carb, It should not.
 
Assuming large hose from the "T" is power brake booster. Eliminate all this stuff to get it running.
 
Murray said:
Assuming large hose from the "T" is power brake booster. Eliminate all this stuff to get it running.
Click to expand...
The large hose "should" be for power brake booster, but looks like it is going to the PCV port on the carb, which is totally wrong. Vehicle has no booster, so fitting on the manifold should be capped, and fitting on carb should go to PCV valve, in the valve cover.
 
Thanks Scott, I've tried that download a number of times without much luck. I have a few service manuals for various cars where I can get a general idea of what I'm looking to do, nothing past 1969 though.
The car is a 72 so perhaps the emissions comment makes sense to me.
Turns out the carb is a 4412-S and at 500cfm it seems like a lot for this car.
The part I'm asking about is the "manifold vacuum tree"?
No power brakes so the largest hose is plugged into the big port on the back of the of the carb.
The 2 ports below that are looped with together with a piece of hose.
The top is plugged and the bottom is hooked to a vacuum port on the front of the carb.

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Mojoe9955 said:
The part I'm ask about is the "manifold vacuum tree"
Click to expand...

Or manifold vacuum fitting. Of which there are a number of styles.

Looks like the one that's there had too many connections so they looped back one and plugged the other.

I'm running a 600cfm Holley with secondaries

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I like what you're putting down Signet and am thinking of doing away with it like you have. You're connected to the back of the carb or the brake booster?
Where does the PCV valve connect?
 
Mojoe9955 said:
I like what you're putting down Signet and am thinking of doing away with it like you have. You're connected to the back of the carb or the brake booster?
Where does the PCV valve connect?
Click to expand...

I went through a process of stripping down so many random wires and hoses that had accumulated over time on the engine and under the dash.
 
I'm going to stick with the carb and eliminate the manifold vacuum fitting and replace with a plug. Connect the PCV valve to the back of the carb and the vacuum advance to one of the ports on the front of the carb then block off the rest. I have been reading up and a little knowledge can be dangerous, so, I'm thinking about switching to electronic ignition or putting in a Petronix and a hotter coil.
 
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That looks like the old vacuum fitting that goes to the brake booster. Your car has seen many modifications over the years and it will take a while to sort it out. You have come to the right place.
 
Mojoe9955 said:
I'm going to stick with the carb and eliminate the manifold vacuum fitting and replace with a plug. Connect the PCV valve to the back of the carb and the vacuum advance to one of the ports on the front of the carb then block off the rest. I have been reading up and a little knowledge can be dangerous, so, I'm thinking about switching to electronic ignition or putting in a Petronix and a hotter coil.
Click to expand...
Make sure it is the ported vacuum port on carb. Depending on which version that carb is, the port could be in the metering block or the body. Easy check is no vacuum at idle. A 500cfm 2bbl. is really 350cfm rated the same delta as a 4bbl. Half a 700 4bbl., more than You really need, but not too bad once You've got everything ship-shape.
 
My vacuum tree had a plug on the big tube, which used for power brake boost. The small tubes are to supply vacuum for accessories like heater/ac controls, & maybe push button Trans control.
 
I doubt that tall vacuum tree is correct for a 1972 slant. I parted a 1974 CA slant (more emissions stuff) and picked another at a salvage yard and recall just a stubby intake vacuum fitting with maybe three 1/8" nipples plus a large top nipple for the brake booster. Whoever connected the large hose to the carburetor's large tube (meant for PCV) probably did so because "same size", though is also just looping the hose since both tap full intake vacuum.
 
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