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Vacuum Source for C4 Transmission

11K views 8 replies 6 participants last post by  rcarleton  
#1 ·
Good evening:

My soon and I are putting the engine into its final setup before it is slated to get its first firing. It has sat around for a wee bit. It is a 1965 coupe with a 289 stroked to a 347. It has Ford over the counter Shelby intake manifold with a QuickFuel HR650 carb. The distributor has the vacuum advance and there is a vacuum port on the side of the carb by the choke. The brakes are manual so no vacuum needed there, but it has a C4 transmission. I have the vacuum line from the vacuum modulator to the back of the engine on the passenger side. On the original manifold there was a port in back of the manifold with a fitting that looked like a threaded rod coupler that the transmission vacuum line screwed into. In about the same spot on the Shelby manifold is a smaller sized opening so the fitting would not work. It is also currently plugged by the engine builder (but can be removed). My understanding is this port had a treaded fitting and then would accept the other end of the PCV hose. I have port on the back of the carb (not the carb spacer plate) that would accept the PCV hose. To achieve the vacuum for the C4 transmission, should I run a T off of the hose out of the carb (with one end to the transmission line, and the other end to the distributor? Or will this impact the idle?
OR should I undo the plug in the back of the manifold, insert the fitting, and run the vacuum off of that? In looking at the top of the manifold, the only two other openings I can find is one for the heater hose inlet and one for the temperature sending unit.

Thank you,

Bob
 
#2 ·
Remove the plug from the rear of the intake and install a hose barb fitting (you can get them at any hardware store).

FWIW, the PCV valve was connected by a molded hose to the carburetor spacer plate, at the rear. NEVER plumb a PCV valve into an intake runner vacuum source.
 
#8 ·
Woodchuck's advise is good in that the "preferred" source for the PCV is the tube at the base of the carb. On the original GT350s , the PCV WAS sourced from a manifold runner and other engines like the 428CJ were also sourced from a front and rear port through a common tube. As time went on , we got smarter about "where" the PCV vacuum should come from. Vacuum for the transmission does not need the same volume as the PCV and is usually sourced from a fitting from a port in the rear. My GT350 is an auto trans ( Hertz rental) car and it used the fitting in the manifold next to the one used for the PCV.
Randy
 
#9 ·
Thank you for all of your responses. I have got the nipple fitting to put the vacuum line into the back of the manifold and got the parts to run the pcv into the back of the carb. For the vacuum line between the side of the carb and the distributor, I am using a rubber vacuum line as both have hose nipples coming out vs a threaded female to receive the threaded flared fitting on a stainless steel line. And the last two items ordered were a Lokar kickdown cable instead of trying to recreating kickdown bar and hose and fittings to get from the fuel pump to the carb fuel line. Pic #1 engine in its current state

I did run into trouble trying to put the a/c compressor support bracket running from the top of the compressor over the valve cover and bolted to the manifold. Two issues were the valve cover is a little higher than the original smooth valve cover and the breather the builder put on I also taller. I put a lower breather on. Then I took off the plate on the compressor and realized that the compressor is not the same setup as the original that came on the car, as that one had two large threaded holes running up the middle vs the 4 holes on the corners on the current one (went with this as it was converted to R134a). This explains why I could not line up the bolt holes. I am not sure if I should be looking for another version of the anti vibration brace, or with this model it may not be necessary? 2nd to 4th pic

We are hopefully will get the Arvinode exhaust installed next week or so.

Bob
 

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