O.k,
So I learned something new, well just become more confused. I did a search on this and would like to get some opinions.
Does both valve covers need to be vented and does one need to be hooked to vacuum to keep the crankcase air clean to keep sludge/acid from forming?

I see some covers don't even have any holes.

Anyways, I ordered two breathers and was going to send one back, never really thought it mattered much. The adapters have to be cut open and I was just going to leave one as a plug.

1.) Can I just use one breather on one side and a plug on the other?
2.) One breather on each side?
3.) Breather and PVC set up, but where would I hook this to a 4150 (Holly DP HP)?
4.) How do people without holes in the valve covers change/fill thier oil?

 

Youll want PCV. The fresh air does the above and keeps the motor clean inside. Breathers still let the blowby accumulate in the engine. Any source of engine vacuum will work. Can even drill/tap a runner and use a barbed hose fitting.

 

Using a runner isn't a good idea, you'll lean out that one cylinder. If you don't have a PCV port on the carb, you can use a carb spacer with a hole drilled and tapped for a hose barb.

 

My bad. I envisioned something like drilling and mounting in the side of the plenum like I did with my previous intake. Got the PCV hooked up. Of course, this is dependant on whether or not theres sufficient room/clearance to mount it.

Edit: this was with tbi, a carb that senses flow may not like that approach unless its a single plane intake.

 

I'm confused, can I just take off from the rear vacuum port on the carb or the manifold port?
I have a thin spacer(1/4"), but it's more like cardboard and is only used to clear the Air Gap/Holly combo. I have hood clearance issues as well so I'd like to use the existing vacuum sources and spacer if I can.

 

No- I'm Confuzed....

I'd hook up the PCV from the rear vacuum port on the carb, and use the rear vacuum tap on the runner for your power brakes. And yes, PCV in one valve cover and breather in the other.

One other thing that works is having one breather in one cover, and using a closed breather with a hose connection to the air cleaner base on the other side. It's the old school way of doing it, but it works too.

 

Thanks for all the help!

I moved the breather to the passenger side and used the PVC from the old engine for the drivers side. I'm going to T off from the brake booster vacuum after the check valve mostly because it would fit perfectly there.

 

Absolutely DO NOT connect your pcv to the brake booster line as a source. If you introduce oil into the brake booster you will cause the booster rubber diaphram to swell and fail. Thats why the check valve is in there so oil vapours don't get into the booster. I would stick to the bottom rear of the carb or a spacer plate. Have you got any pics of your carb? Its not very fun trying to stop these tanks when your power brakes fail!

 

O.k, then I'll do it that way. The check valve is at a right angle and would line up perfectly- Too good to be true.

Thanks for your input. I probably would have assumed it just went bad and gone through a second one not knowing. Let alone gettting a nasty suprise!

The brake booster goes to the rear of the carb as well (Stock set up), which is why I was going to do it that way.

So if I "T" it off close to the carb I should be O.k? As long as I'm on the farther side of the check valve from the booster? Or do I need to seperate it completely? I have clearance issues with the hood and the spacer that I already have won't accomodate a tap. The carb is a Holly 4150 DP, The only large port is off the rear of the carb.

 

OK, I don't know what intake you're running, but there is a large vacuum port at the rear of your carb - I use that for PCV only. For the brake booster, I run a intake very simular to a RPM air gap, and there's a plug for a vacuum fitting darn near underneath the secondary fuel bowl on my Demon carb on top of the rear runners.

I had to buy a "low profile" 90 degree vacuum fitting to hook the brakes up to. What I further found out, that even with this special fitting, I still didn't have enough room and the carb would not sit flat on the intake (bottom of the bowl hit the fitting), so I used a 1/2" carb spacer to bring the carb up out of the way, and the problem was solved. Two separate fittings for brakes and PCV - that's what you want. If you tee off your brake booster with the PCV, your booster will NOT have enough vacuum left to operate properly - or at least mine didn't. Hope that helps!!

 

Since confuzed1 has the same set-up I would set it up like his. Just stay down stream of the check valve so you keep your chances of contamination to a minimum.

 

Yes this helps a lot, I do have the Air Gap with the same interference issues. I resolved mine by using a Holly spacer (108-12) with the stock vacuum piece. It barely fits and I don't know if it will clear the hood as it is.

The stock port is a lot smaller than the brake booster line. Looks like I need to change to an aluminum spacer or run the PVC from the manifold. I’d like to keep the brake booster in the same location as stock though.

Where do you take the vacuum advance and cruise/accessory vacuum on your set up? Mine is off of the manifold location.

Sorry I didn't post my set up, I posted something similar on another thread and thought I did it here. Here's some pics but they don't show the Holly carb very well.
And the thread:
https://www.thirdgen.org/techbb2/sho...hreadid=324430

 

The other pic, you can see the rear vac port and clearance issue common with many.

 

Thanks again, I'll find a way to keep them seperated.

 

this question go to Confuzed1, I am also running the air gap intake and a 4150 (4777) still having problems with mine did you but the edelbrock low pro fitting or another. The tech from edelbrock said it was specifically designed for this purpose. I haven't even had time to try it yet. also if you are running a 1/2 spacer what size air cleaner are you using? thanks in advance. do by any chance have a pic. also by anychance anybody on here have a wiring harness mine is missing the tranny plug and I already set it up for vacuum lock up.

 

jstoltz,

I run a Demon carb, but it's pretty much the same. I bought the Edelbrock low profile fitting but still had to add a 1/2 inch wood spacer. "Specifically designed for this purpose".....Edelbrock's full of it though, cause it's not "Low Profile" enough to use with a regular gasket only.

So far as my air cleaner, it's a cheapie that does the job, but ain't fancy...part #720-4339 14'' Diameter / 2-1/4'' High Low Rider Air Cleaner - Jeg's. I'll see what pics I have.

 

Here's a couple:

 

2.

 

does it matter which side the breather/pcv is on? I wouldn't think so but my driver side valve cover is up front and passenger side is in the rear. it would just be opposite of yours. Thanks

 

Shouldn't matter at all, so long as both valve covers have baffles - and most do.