Pcv?

[DJ_Baar]

I got this '67 C20 with a 350, only thing changed (from the 327). Question is it had no PCV and blowing a lot of oil thru vent (front of intake). So I changed the valve covers for a PCV fitting - but what is correct connection at carb. I thought into the air cleaner would work, but kit to add that is too BIG to use. And have a power brake booster that is connected to vacuum at front of carb. Here's a couple pictures before I changed valve covers.

R/
DJ

[firedemon]

you should have a port at the intake somewhere

[davischevy]

Your power brake goes into the back of the carb or into the vacuum port in the rear of the intake, depending on year. The port In the front of the carb, where your brakes are now, is where the PCV goes.

[1970 charlie]

There are two types of vacuum, ported and manifold, ported is above the throttle plates and manifold
is below the throttle plates. For the pvc you want manifold so that would be at the base of the carb or a manifold port.

[DJ_Baar]

That's what I thought --- trying to find that correct port for power brakes.

[DJ_Baar]

Anyone got a picture of what is correct for PCV & Power Brake Booster?

[geezer#99]

Take a pic of what you have at the back of your carb and then we can point you in the right direction.

[DJ_Baar]

I will do my best to get a good picture in morning behind carb.

[swamp rat]

The center back of the Edelbrock carb, it has a port that is manafold vacuum as its below the throttle plates, it may need an adapter to attach the proper size hose barb for the booster, also on the intake, if its a performer then there will be a plug right behind the carb, the brake booster can go to ether spot.

On the front the center port is also manifold vac as is the small port on the right (Driver side), the small port on the left ( Passenger side) is above the throttle plates, Ported vacuum, and go's to the distributor.

[DJ_Baar]

From Swamp Rat, "On the front the center port is also manifold vac as is the small port on the right (Driver side), the small port on the left ( Passenger side) is above the throttle plates, Ported vacuum, and go's to the distributor." That means the distributor is currently on wrong port. Also distributor vacuum line is tee'ed for other going (I assume) to TH400 trans shift dash pot, is that right?

Also from Swamp Rat, "The center back of the Edelbrock carb, it has a port that is manifold vacuum as its below the throttle plates, it may need an adapter to attach the proper size hose barb for the booster, also on the intake, if its a performer then there will be a plug right behind the carb, the brake booster can go to ether spot." I took pictures this AM (attached) and sure enough two (2) ports to put a barb on. And either on on base of carb or in manifold will get the correct vacuum for PCV because below throttle plates?

Also to 1970 Charlie, "There are two types of vacuum, ported and manifold, ported is above the throttle plates and manifold is below the throttle plates. For the pvc you want manifold so that would be at the base of the carb or a manifold port." I TOTALLY appreciate all this advice!!! This old grey beard was a bit ignorant on these vacuum ports.

Thank you Guys BIG TIME! Sorry for more questions, just want to get it right.

DJ

[geezer#99]

Pcv hose goes in the front of carb.
Booster hose hooks into rear of carb or your intake.
You use a vacuum tree. There's a gazillion styles. Auto parts store will have some.
https://www.google.com/search?site=&...ld+vacuum+tree
You need one for your booster hose and your modulator line to the tranny.
Your distributor gets either the ported or manifold barb. Let your motor decide.

Kudo's on the excellent pics!

[DJ_Baar]

I was out getting the right fitting for back of carb on manifold. I went ahead & connected PCV there since it doesn't interfere with throttle connection like brake booster would. Left brake booster at front of carb - at least for now.

I'm replacing brake booster, master cylinder, and proportioning valve with CPP unit since using '71 GMC 3/4 ton disk brakes. (Changing spindles, tie rod ends, misc. parts, too.)

Thank you all for your help!

DJ

[dflarsen77]

Looks like I'm too late, but for mine I just googled "edelbrock 1604 ports". And found several pics like the one below. It looks like you still have your distributor on the mani port, should be on the timed port, although I have read some people use mani vac. Timed port has no vac at idle and then builds vac as engine speed rises, which is how the distributor vac advance works, which is why it's supposed to go there. I would think your advance would be kinda bananas on the mani vac port.

It looks like another line is teed into it tho, which should be the charcoal can, but it looks like it connects to a hard line in the back, which would be the trans vacuum modulator line. That trans vac line should go to the little manifold vac port on the right of the big pcv port, and the distributor and charcoal can (if you have a can) would go on the left.

For the brake booster port in the back, you just need a 1/4 npt mal thread to 3/8 hose barb and it will work with the 3/8 hose from the brake booster, but it looks like you got that sorted.

I'm not sure why but everything says the pcv should go to the front port, not the rear. I really don't see why though, as they're both mani vac. But like you said, that pcv hose wants to be in the way of your throttle stuff. Just show that hose who's boss!

[DJ_Baar]

Thank you dflarsen77, I didn't think to check Edelbrock site for specs --- Doooh

I see I can route the PCV or Brake booster either way as booster will come under the throttle rod - but like you say that is same "manifold vacuum."

I did change the distributor vacuum line to left (passenger) side timed port.

I noted that ALL the small vacuum lines for A/C, distributor, & transmission were tee'ed-off of same distributor vacuum line.

will route the trans vacuum modulator line to one on right and assume can leave the A/C to that?

Thank you for helping me sort this all out!

DJ

[DJ_Baar]

Found this and explains a bit more on carb vacuum connections. https://www.youtube.com/watch?v=Gj2utt1oSQE