Vacuum Question

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I don't know that I would tee the PCV and brake booster because if the PCV sticks open, you lose vacuum to the brakes? Then on the other hand, how is that different than having it to 2 ports on the base of the carb? Interesting conundrum for sure.......

I was suggesting that you use the small ports for the trans governor. The PCV and booster need volume, so that's why they're 3/8 vs 1/8 line sizes.

Isnt the PCV open constant with manifold vacuum anyway ?
 
What type of 90 degree fitting are you using into the intake, Brass, Plastic, Steel?
While not a great shot this is a better picture of how I modified the brass fitting on my 406. If you are using a brass fitting why not drill and even solder a piece if 1/4 tube into it for your vacuum modulator? It would keep all that at the rear of the engine.

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No, it's a controlled leak with the check ball- closes with less vacuum.

So, another friend of mine suggested hooking the PCV to the air cleaner. I had that setup on my 72 Nova. Used one of these fitting kits. What do you think of that ? Pros/cons ?
 

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What type of 90 degree fitting are you using into the intake, Brass, Plastic, Steel?
While not a great shot this is a better picture of how I modified the brass fitting on my 406. If you are using a brass fitting why not drill and even solder a piece if 3/16 tube into it for your vacuum modulator? It would keep all that at the rear of the engine.

View attachment 133023

I used this fitting made by Edelbrock. It was the only one I could find that would fit under the bowl without a spacer.
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I used this fitting made by Edelbrock. It was the only one I could find that would fit under the bowl without a spacer.
View attachment 133030


I had that one also, but did not use it. On one of the flats you could drill and solder a piece of 1/4 brake line to use for the vacuum modulator on the transmission. as far as the PCV and brake booster I don't imagine it would matter if those were both ran off the same 3/8 line. The pcv line under the air cleaner is a great idea rather then using a push in filter in one of the valve covers. Makes it a closed system like GM had.
Just my thoughts.
 
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So, another friend of mine suggested hooking the PCV to the air cleaner. I had that setup on my 72 Nova. Used one of these fitting kits. What do you think of that ? Pros/cons ?
That's for the inlet side of the PCV system (valve cover opposite the valve)= no suction.
 
Just keep in mind that this all subject to change once you drive it. If the cam doesn't create enough vacuum to run the brakes, you're going to have to abort the PCV system and just run breathers. My Olds 468 didn't like the PCV at all because it's a little on the loose side with piston to bore clearance, and it would push the valve out. I had to go to strictly breathers to alleviate it, but I could always add a vacuum pump and catch can if I really wanted to blow some money.
 
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