Old Guy with Short Memory needs Refresher Course, Please
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Drifting
Joined: Nov 2000
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Old Guy with Short Memory needs Refresher Course, Please
Vacuum Gauge on my '76 350 w/mild street cam pulls down to 16-17 or so, when hooked to distributor vac. advance, at idle. Is this good, bad, or ugly? Thanx in advance for any and all replies......TNT76VET
Le Mans Master
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From: Semper ubi, sub ubi
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Re: Old Guy with Short Memory needs Refresher Course, Please (tnt76vette)
16 or 17 is fine as long as it is fairly steady. Your mild cam probably cause your vacuum to be down a couple of inches. With a grocery getter you can expect about 19-21 inches on an engine in good condition and tune.
Make sure you check it from full manifold vacuum, don't trust you advance line, it is probably coming from a ported vacuum source on the front of your carb.
Make sure you check it from full manifold vacuum, don't trust you advance line, it is probably coming from a ported vacuum source on the front of your carb.
Burning Brakes
Joined: Aug 2000
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From: Katy TX
Re: Old Guy with Short Memory needs Refresher Course, Please (tnt76vette)
If it is 16 or 17 you need a bigger cam :)
No, really it sounds fine. For a point of reference I have a comp cams magnum 270H and I tune the motor in right at 15" of vacuum. All of the vavuum operated stuff sill works fine. I wonder how low the vacuum can go before your brakes and headlights stop working right???
[Modified by PatG, 11:34 PM 2/9/2002]
No, really it sounds fine. For a point of reference I have a comp cams magnum 270H and I tune the motor in right at 15" of vacuum. All of the vavuum operated stuff sill works fine. I wonder how low the vacuum can go before your brakes and headlights stop working right???
[Modified by PatG, 11:34 PM 2/9/2002]
Melting Slicks
Joined: Dec 2000
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From: Wichita, KS
Re: Old Guy with Short Memory needs Refresher Course, Please (tnt76vette)
Uhh, great vacuum, but why are you getting it at the dist. at idle? The dist. should be getting no vacuum at idle. I think that it's the drivers side port on the front of the carb. that is for the dist. Should be no vacuum befoe 1200 RPM or so.
C6 the C5 of tomorrow
Joined: Nov 2000
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From: Twin Cities Minnesota
Re: Old Guy with Short Memory needs Refresher Course, Please (PatG)
Yea a bigger cam will bring that vacuum down, a good high duration cam will have less than 10" vacuum...:smash: :smash:
If it is 16 or 17 you need a bigger cam :)
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