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Where do I find a diagram of the vacuum line routing for 69 351w 4V, Does have front disc brakes with power steering no AC and manual transmission. I know the 3/8 line on the back of the intake goes to the brake booster. But where do the ¼ vacuum lines from the carb & distributer go? Is there a vacuum tree on the intake thermostat housing?? Any help appreciated
 

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Where do I find a diagram of the vacuum line routing for 69 351w 4V, Does have front disc brakes with power steering no AC and manual transmission. I know the 3/8 line on the back of the intake goes to the brake booster. But where do the ¼ vacuum lines from the carb & distributer go? Is there a vacuum tree on the intake thermostat housing?? Any help appreciated
I found a picture of what I beleave to be a 69 4V 351w with a vacuum Tree in the thermostat housing. But would this be correct for my engine as discribed ? Looks like some did some did'nt ?
 

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The "vacuum tree" was a temperature sensing device that rerouted the vacuum from "timed" vacuum to "manifold" vacuum when the coolant temperature reached a certain level- hot. Sending manifold vacuum to the distributor advanced the timing causing the engine to speed up and the fan to turn faster. If you're not worried about Concours Correct you can just connect the vacuum advance to a manifold vacuum source either in the intake or in the base plate of the carb.
 

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Yep, the "tree" is a Distributor Vacuum Control Valve. It's function is to increase idle speed in case of overheating to cool the engine.

Oddly enough, the 69 351W without AC had "old school" advance, with no DVCV.
757408

 

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B980, what is the goal here ? Are you trying for exactly factory correct, which can be difficult as some did and some did not, or do you just want what works best and is driveable and gets good mileage ? LSG
 

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B980, what is the goal here ? Are you trying for exactly factory correct, which can be difficult as some did and some did not, or do you just want what works best and is driveable and gets good mileage ? LSG
I think the answer would be to do what works best and is driveable and gets good mileage
Is there really a difference eather way with or without the DVCV ?
 

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BOSS, yes, there is a difference. The DVCV is an emmissions device that DISABLES the vacuum advance so that the temperature is higher in the exhaust ports. It does not let full vacuum through until the engine is just about to overheat. I remove them every chance I get. It was an early attempt to reduce unburned hydrocarbon emitted at idle. It makes the engine run hot and eat fuel. The best way to go is to skip the DVCV and run full manifold vacuum all the time. LSG
 

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Yep, the "tree" is a Distributor Vacuum Control Valve. It's function is to increase idle speed in case of overheating to cool the engine.

Oddly enough, the 69 351W without AC had "old school" advance, with no DVCV.
View attachment 757408
So, my car, being a 69 with a 72 351W and T5, my vac advance is attached to the carb (Holley 4160, side, not the base). Am I to assume it's better to have the VA attached to the manifold rather than the carb? New one on me, but if so, I'll do it.
 

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Frankie, I think the side port is for 'ported' vacuum, which you don't want. Try it on the connector at the base of the carb, and see if you like it . LSG
 
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