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Engine vacuum

  • Thread starter Thread starter KAWMAN2
  • Start date Start date Aug 1, 2026

KAWMAN2

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Aug 9, 2022
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Aug 1, 2026
#1
  • Aug 1, 2026
  • #1
can you eliminate the vacuum ball for the a/c door and go strait to manifold vacuum?
 

Mcmahst

5 Year Member
Jan 19, 2021
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Laguna Woods CA, fort Mohave AZ
Aug 1, 2026
#2
  • Aug 1, 2026
  • #2
No. Longer answer is, the ball is the reserve you’ll need when climbing a hill with the AC on. No ball, door closes half way up the hill and ain’t no one happy with no air.
 

KAWMAN2

Member
Aug 9, 2022
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32962
Aug 1, 2026
#3
  • Aug 1, 2026
  • #3
No hills in Florida, I bypassed the ball and ran it hard today’s/c worked fine, but I will teplace the check valve and ball
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
Aug 2, 2026
#4
  • Aug 2, 2026
  • #4
My answer would be a question, why eliminate the ball and check valve?
 
Reactions: Mcmahst

KAWMAN2

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Aug 9, 2022
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Aug 3, 2026
#5
  • Aug 3, 2026
  • #5
very hard to find down my way!
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
28,059
10,684
213
polk county florida
Aug 3, 2026
#6
  • Aug 3, 2026
  • #6
Yours leaks?
Nobody thinks of saving those things.....cept me. PM me if you need it.
If you delete it the blend doors are set for defrost mode at vacuum loss so you hit the gas and the vacuum drops the blend door will switch back and forth as vacuum falls and rises but will not effect how the engine runs.
 

KAWMAN2

Member
Aug 9, 2022
65
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32962
Aug 3, 2026
#7
  • Aug 3, 2026
  • #7
I thought the same thing I have a 331 strokker when i pour the coal to it it still blows air out the/c vents nothing out the defrost till i switch it to defrost, I do have a air gap manifold and a 850 cfm holley on it with a full race cam? the engine does not create a bunch of vacuum ?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
28,059
10,684
213
polk county florida
Aug 3, 2026
#8
  • Aug 3, 2026
  • #8
There are two vacuum bulbs under that right fender, one is for (IIRC) emissions stuff. It's shaped a little different.
 
J

Jarhead67

5 Year Member
Nov 24, 2018
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Windsor Locks, Connecticut
Aug 4, 2026
#9
  • Aug 4, 2026
  • #9
KAWMAN2 said:
I thought the same thing I have a 331 strokker when i pour the coal to it it still blows air out the/c vents nothing out the defrost till i switch it to defrost, I do have a air gap manifold and a 850 cfm holley on it with a full race cam? the engine does not create a bunch of vacuum ?
Click to expand...
I had the same problem of low vacuum, I installed a vacuum pump. EZ PZ
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,340
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Massachusetts
Aug 7, 2026
#10
  • Aug 7, 2026
  • #10
WOT or high load hits where vacuum drops is where you might have issues. You might find depending on your settings that the vacuum blend doors will move under load due to not having the vacuum ball in place, but when you lift they should go back to where they were.

How much you notice this will depend on what hvac settings you use and how quick the vacuum tapers off
 
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