Need a good source for a vacuum signal

82 GT · 06-07-2006, 06:25 PM

Where would be a good place to get the best vacuum signal for my gauge? I "wanted" to use the port on the back of my intake but the fuel inlet lines block access to it. The only way to get to it is if I use a carb. spacer but I don't want to do that right now.
Could I use the small vacuum port on the front of my holley as a reliable source?
I want to get a vacuum reading during full throttle to see if I have the best power valve or not. Right now it's a 6.5

Rev · 06-07-2006, 07:42 PM

Use the port at the right front of the Holley. There are 2 ports there, one for manifold vacuum and one for ventouri vacuum. You want the manifold vacuum port. That's the one that will read some vacuum at idle (probably only 6-8" Hg with your cam).

I think you should use a 4.5 power valve ot there about since you really don't want it to actuate unless you put your foot in it some.

Rev

06-07-2006, 06:25 PM	#1
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	Need a good source for a vacuum signal Where would be a good place to get the best vacuum signal for my gauge? I "wanted" to use the port on the back of my intake but the fuel inlet lines block access to it. The only way to get to it is if I use a carb. spacer but I don't want to do that right now. Could I use the small vacuum port on the front of my holley as a reliable source? I want to get a vacuum reading during full throttle to see if I have the best power valve or not. Right now it's a 6.5 __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator.

06-07-2006, 07:42 PM	#2
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Re: Need a good source for a vacuum signal Use the port at the right front of the Holley. There are 2 ports there, one for manifold vacuum and one for ventouri vacuum. You want the manifold vacuum port. That's the one that will read some vacuum at idle (probably only 6-8" Hg with your cam). I think you should use a 4.5 power valve ot there about since you really don't want it to actuate unless you put your foot in it some. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

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