how many vaccuum tee's are too many???

[01maroonz71]

well, right now i have my T400 trans line, my brake booster, and my pcv valve coming off the same manifold vacc. port on my holley, my carb only has one port...and my manifold has nothing as far as that goes. should i drill tap a new one(pull manifold off, PITA!) or should i throw another tee in there...im gonna try runnin my vacc. advance off full manifold instead of ported....would that be ok???? or no???
thanks
~Dave

 

[cybrfire]

well, right now i have my T400 trans line, my brake booster, and my pcv valve coming off the same manifold vacc. port on my holley, my carb only has one port...and my manifold has nothing as far as that goes. should i drill tap a new one(pull manifold off, PITA!) or should i throw another tee in there...im gonna try runnin my vacc. advance off full manifold instead of ported....would that be ok???? or no???
thanks
~Dave

that's a big no on full vaccum to the advance. Sorry.

 

[Chevy305]

What Holley are you running? Mine has 2 full vaccum ports. And my manifold has 1.

Your Holley should have a port specified for your vacuum advance. Its located on the passenger side towards the front of the carb, right above the idle air screw adjustment.

 

[01maroonz71]

yeah, but that is ported vac. on my holley(where it says to hook too) and because of my cam, i have been told by ALOT of people to try manifold vac to see how she idles/runs. right now the idle is acting goofy, and i think that may be my problem no to mention there is a huge post on here about why manifold vacc. is better than ported. just figured i'd try it to see how she runs/idles.

 

[Chevy305]

If you need another vac port, there are carb spacers setup for a vacuum bung thingy. I'll see if I can find you a link...

 

[Chevy305]

 

[01maroonz71]

oh i see...ill look into that for sure...i have a 4160carb 750CFM dual feed fuel and im 90%positive i don't have another manifold vac. port, but i will look again, if i don't...then ill have to go with one of those spacers i geuss.
thanks!!!

 

[diesel4me]

either way ok....

Some engines run better with ported vacuum ,some don't..only way to find out is trying both ways..wont hurt anything,GM used both ways depending on year and emissions..

I'd make sure there is no threaded plugs you can remove to add another vacuum hose nipple too in the intake..maybe you can tap a hole ,some manifolds have a "boss" that would have been a vacuum source, that wasn't drilled and tapped at the factory..

It's best to keep the PCV valve on its own separate vacuum source..oil vapors can eat the rubber power brake booster diaphram..GM uses a charcoal canister in-line to the booster,if they had it hooked to the same hose the PCV valve gets its vacuum from..also,if it gets insufficient vacuum ,it will encourage blowby, and oil leaking past seals and gaskets..