Slant Six Forum :: Relocation of PVC Vacuum Source.

Keep in mind that hole is not used for PCV on carbs made after about '67-'69 (it's in that year range, not sure exactly when). That's when the PCV port was moved over to the inboard side of the BBS and 1920 carburetors, which gave better overall mixture distribution and required no separate pass-thru port in the carb mounting pad on the intake manifold. That pass-thru, however, is used for manifold vacuum to the thermostatic air cleaner on 1920 thru '72, BBS thru '74.

Author:	wjajr [ Fri Jan 09, 2009 5:05 pm ]
Post subject:	Relocation of PVC Vacuum Source.
I recently rebuilt my Holley 4160 390 CFM carburetor that sits on a Clifford intake manifold. All went well with the rebuild, and the car started right up as soon as she got a taste of gas. This car has an unidentified Erson cam, and doesn't like any RPM below 650 as vacuum gage needle starts to osculate with vigor around that speed. Previous owner had install a nipple on the side of the manifold centered below the carburetor for the PVC valve vacuum source. I caped that port off, and used the large nipple located at the base of the secondary half of the carburetor as the vacuum port for the PVC valve to lessen looping hose festooning the engine bay. It seems that the idle is now smother. Is this just me, or is there a reason for this change?

Author:	steponmebbbboom [ Fri Jan 09, 2009 5:23 pm ]
Post subject:
yes, dan just spoke about this today in another thread: Quote: Keep in mind that hole is not used for PCV on carbs made after about '67-'69 (it's in that year range, not sure exactly when). That's when the PCV port was moved over to the inboard side of the BBS and 1920 carburetors, which gave better overall mixture distribution and required no separate pass-thru port in the carb mounting pad on the intake manifold. That pass-thru, however, is used for manifold vacuum to the thermostatic air cleaner on 1920 thru '72, BBS thru '74.

Author:	68barracuda [ Fri Jan 09, 2009 10:02 pm ]
Post subject:
osculate with vigor around that speed................................finger trouble since osculate menas to smootch

Author:	wjajr [ Sat Jan 10, 2009 1:34 pm ]
Post subject:
Sothern Hemisphere Guy, 68barracuda writes: Quote: osculate with vigor around that speed................................finger trouble since osculate menas to smootch Hummm. Not here just 10 minutes north of the 45 th. parallel, we think of it as fluctuating, not to be confused with swinging both ways.

Author:	SlantSixDan [ Sat Jan 10, 2009 2:34 pm ]
Post subject:
Ah, you're @ the 45th Parallel? Weird things happen @ the 45th Parallel, and there's just no explanation other than "it's the 45th Parallel". Just ask Svensk Slanter! "Swinging both ways", you mean like a Mopar ammeter needle at night with in a traffic jam with the lights, heater, radio, and wipers on, right?

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