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Discussion Starter · #1 ·
These are some vacuum related items my friend and I pulled off when we were doing a 4bbl upgrade. What are they for and do we still need them? Also the edelbrock intake has a hole in the #4 runner, is that a place we can put the stock vacuum tree that feeds trans, booster, and C/C?

 

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I think that was called a venturi vacuum amplifier or something. IIRC Its function was to take a weak venturi vacuum signal and use it to modulate manifold vacuum for the EGR. Think of it as some fine 1970's economy....err emissions reducing equipment.

If you live in an area with emissions testing you might be required to have it!:banghead

As for the #4 runner....you can run the trans from there. If it were my truck, I would locate the Brake Booster, Cruise, etc to the carb spacer plate and the PCV to the port on the carb.
 

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I'm not sure what that part is actually called, but I would call it one of those "extra" parts ford felt the need to slap in there. I ripped all that crap out of mine...threw it away and didn't look back.
 

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Yep, BigWheelz wins the prize, it's a vacuum amplifier with related check/delay valves.

You can try the vacuum tree connected to the #4 runner. If you get pulsing vacuum there, install a fitting nearer the carb, away from the runners.
 

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Discussion Starter · #5 ·
Thanks guys. Looking at the stock intake where the vacuum tree goes it looks like it has two small ports in the intake going to the #4 and #8 runner. I was just wondering if all the vacuum is fed from just the #4 runner on the 4bbl intake that it might cause that cylinder to run rich?
 

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I will take those parts if you want to get rid of them
They really worth or good for anything? I think I still have mine (somewhere). I'll bet even Scott being the parts collecter with everything that he is would throw that stuff in the garbage in a heartbeat:toothless
 

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Thanks guys. Looking at the stock intake where the vacuum tree goes it looks like it has two small ports in the intake going to the #4 and #8 runner. I was just wondering if all the vacuum is fed from just the #4 runner on the 4bbl intake that it might cause that cylinder to run rich?
No, taking the vacuum from #4 won't make that cylinder run rich/lean. A vacuum 'leak' there would have an effect, but since it's a closed vacuum system it won't.

I'm sure Edelbrock has done all sorts of flow testing on that manifold, and if the vacuum port being on the #4 runner was a problem, they'd have discovered it and moved it elsewhere. Since the vacuum port's already there, I'd try it and see how it works before drilling another port.....
 
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