Vacuum diagram for my truck? Would you be able to "decode" it for me?

Tiny
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Is it coming from the vacuum modulator on the transmission? If it has a steel line, chances are that is what it is. Look at the transmission and locate the module. See if it attaches to the steel line. If I recall, it will be mounted near where the transmission dipstick tube is mounted. If that, is it, it simply gets engine vacuum.

If the vehicle has a carb (I don't think it does, but don't recall asking), it will mount to the bottom of the carb at a vacuum port.

Let me know. See pic below.

Joe
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Wednesday, September 29th, 2021 AT 9:08 PM
Tiny
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Great, thanks. Yes, it’s a steel line, as you described, and yes, I have a carb. Does it matter what port it connects to on the bottom of the carb?
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Wednesday, September 29th, 2021 AT 9:14 PM
Tiny
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Hi,

I said that backward. The base of the carburetor is ported vacuum. You need a manifold vacuum. There should be a nipple behind the carburetor on the intake that it goes through.

Take care,
Joe
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Thursday, September 30th, 2021 AT 6:09 PM
Tiny
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Okay, cool. So, the distributor should hook up to the large vacuum port in the middle of the carburetor in the back side, and then there is a small nipple just next to it, that’ll be for the transmission line?
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Thursday, September 30th, 2021 AT 6:56 PM
Tiny
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If it is on the manifold, yes. It's been some time, but I remember the vacuum being attached to the intake manifold behind the carburetor.
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Thursday, September 30th, 2021 AT 7:09 PM
Tiny
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The only one I have on the manifold behind the carburetor is a large vacuum port, and I have the brake booster connected to that.
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Thursday, September 30th, 2021 AT 7:11 PM
Tiny
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Okay, try using one from the base of the carb. It shouldn't make a difference. The worst case is a slower response from the modulator. However, I can't imagine it would even be noticeable.

That's a whole lot of engine! LOL

Hopefully, when you get it running, you can videotape it and upload it for me to hear.

Take care,

Joe
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Thursday, September 30th, 2021 AT 7:19 PM
Tiny
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To confirm; distributor needs ported vacuum, and transmission line needs manifold vacuum? I think I have them reversed right now.
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Monday, November 29th, 2021 AT 9:52 PM
Tiny
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Hi,

Yes, the distributor should be ported. The transmission responds to a drop in vacuum, so you want a manifold vacuum.

Looks great. Let me know how things turn out for you.

Take care,

Joe
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Tuesday, November 30th, 2021 AT 3:42 PM
Tiny
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Thanks Joe. What about the rear vacuum break assembly? Ported or manifold? Or just plugged?
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Tuesday, November 30th, 2021 AT 9:23 PM
Tiny
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Hi,

It appears you circled the choke pull-off. That will be a manifold vacuum.

Joe
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Wednesday, December 1st, 2021 AT 7:54 PM

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