So many vac lines !!

[81squared]

I am new to later model 350s, there are a ton of things on this intake and carb that Ive never seen.

Let me preface... Im installing a Holley Sniper EFI complete system, rather than try to figure out what I have going on vac tube wise, let me ask this...

After the carb is gone and the edlebrock intake with the holley EFI installed what will require vacuum still ?

The brake booster obviously and the one one going to the valve cover, what else will require vacuum ? my Dist will be a hyperspark, they do not have vac advance on them, so im not sure what I will need to mend up after the carb is gone.


this pic shows a metal vac line possibly ? what does this do ?

one under it shows a filter on the brake booster vac line ? necessary ?

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this pic below is showing the wire in the back of the intake ... is this a idiot light wire ?

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there are many many vac lines around this carb, i really hope they are all gone after EFI , any help here would be helpful...

Im having a very knowledgable friend help me with the EFI conversion I just want to be ahead of the curve on these questions

thanks

 

[Matt69olds]

You will need the vacuum line that supply’s vacuum to the climate control. There are 2 plastic lines, one is connected to the vacuum ball, the other goes to the heater control valve. Iftgetruck has cruise control, you will need the line to the vacuum servo. If the trick has a 350 or 400 trans, you need a vacuum source to the vacuum modulator.

That should cover about everything.

 

[78C10BigTen]

The (metal) one on the pass side that you have yur finger on is the same as on my 78, mine is broken and wide open but it dont effect anything. That wire to the "idiot light" looks to me as the oil pressure light.
People smarter then me will chime in soon.

 

[81squared]

You will need the vacuum line that supply’s vacuum to the climate control. There are 2 plastic lines, one is connected to the vacuum ball, the other goes to the heater control valve. Iftgetruck has cruise control, you will need the line to the vacuum servo. If the trick has a 350 or 400 trans, you need a vacuum source to the vacuum modulator.

That should cover about everything.

I assume a lot of what you mentioned runs through the vac system of the carb ?

Once the carb is gone i just re route lines to items you mentioned... auto trans, heater controls, there is a port on the thermo housing, is that what I would need to feed these items in need of vac ?

 

[SirRobyn0]

You'll need to feed the following things manifold vacuum.
Brake booster, PCV valve, Climate control, if you have a TH350 auto you'll need to feed the vac modulator on the trans. Off the manifold is fine or off the throttle body for the EFI if it has a non-ported port. Climate control will need a one way vacuum check valve (or reuse the one it has) otherwise it won't work properly when vacuum is low, such as climbing a hill.

If you are running a charcoal canister and there really is no good reason in my opinion to remove it, you'll need to plug the bowl vent line on the canister since the carb is gone. You can tee the big vacuum line into the PCV hose, and then there is a smaller line that will need ported vacuum or to be hooked to a solenoid that will control it.

If your EFI system will have an EGR valve, you'll need ported vacuum for that or follow EFI manufactures recommendations. I would recommend that you do keep the EGR valve if possible, mainly because it helps a little bit with fuel economy, but also lowers combustion chamber temps at cruse which equals longer engine life and lowered emissions.

The thing you have your finger on is the choke stove for the carburetor. Pipes a small amount of heat up to the choke to help it open. Often times they'll stop working and guys will get electric choke kit just because it's easy. Obviously you won't need this after the conversion.

Side note, unless your keeping the parts you take off please consider selling or giving some of it away. A lot of those little things, like the vac temp controller, choke stove and various other piece of the vacuum system are long out of production and now made of unobtainium.

 

[81squared]

I will be donating whatever is salvageable. I will post a list of parts when I have everything off the motor.

 

[81squared]

What kind of alternator is this ? A 3 wire ? Or a 1 wire ?

These ports on the other photo … can all these be eliminated? I was hoping for a regular t stat housing like the older models

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[Raider L]

@81squared,

On this year motor, this Alt. could be a 10 SI or more than likely a 12 SI 3 wire.

Question, don't all those vacuum tubes on those stands coming off the water in the intake, don't those go to a bunch of vacuum operated do-dads, not carb, but other stuff? I don't know, other than they are hot water actuated, the little thing inside opens and vacuum is being drawn at the bottom and when the hot water operated thing opens then there is vacuum on the ones at the top. Or the other way, vacuum at the top, then heat opens it up and then vacuum at the bottom. Whatever.