Ported Vacuum

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Calvin Gunter
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Ported Vacuum

Post by Calvin Gunter »

We rebuilt my 600 holley last year and now I have 17 lbs. of ported vacuum.What did we do wrong?I'm thinking maybe wrong metering plate gasket or wrong power valve.I can't get my Mallory Unilight to time right at idle because of this.Any suggestions?TIA,Calvin
1967 Ranger,Short bed,390,C-6,9 inch,4 BBL.,intake,cam,headers,3:55 Posi.,A/C,Power steering,Power Disc Brakes,Automatic trans.DJM dropped I-beams,flipped rear hangers,headlight harness upgrade.ExTang tonneau cover "Old Blue".
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1967 Base model,352,2bbl.,3 on the tree,short bed,3:25 9 inch "Rusty".
1967 Mustang coupe-show car/garage queen.Small Block,alum. heads,Nitrous,4:11Locker,Areospace brakes "Mystang".
1996 F-250 Powerstroke-Big intake,exhaust,injectors.(Nice Smoke Show) "Big Sexy"
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george worley
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Re: Ported Vacuum

Post by george worley »

It;s just a thought but did you check the neww gaskets against the old ones so see if they match.From what you said it sounds to me like a gasket problem.I don't think a power valve would cause your problem. Could you be on the wrong connection.
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FoMoCo
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Re: Ported Vacuum

Post by FoMoCo »

You should have zero vac at idle on the vac advance port. If you ditributor is receiving vac it idle it will cause your advance to work in reverse and retard timing when it needs advanced. Make sure you hooked up to the port on the metering block and not a port off the base.

Nick
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