correct valve cover cap for L48 engine

[Nigel]

Dear Sirs

I have a 1968 RS/SS Camaro with the L48 350 engine. When I purchased the car it had an Edelbrock cap on the valve cover (see attached photo) however I would like to replace this with the correct one for the car.
I am going to place an order with heartbeatcitycamaro for a couple of parts and would like to order this correct part as well. Please can you advise.
Mnay thanks, Nigel

[bertfam]

That cap is taking up the spot where the PCV valve and hose to the carburetor goes (see below).

Ed

[Nigel]

Hi Ed, Thanks for your message. Please excuse my ignorance regarding the pcv valve & hose, I only know the engine basics. I have been driving the car like this for over a year. Is that a problem and do I need to purchase a pcv valve and hose?

Mnay thanks once again, Nigel

[bertfam]

The cap you have is probably "vented". To verify, check underneith and see if there are holes all the way around the perimeter. If there are, it's "vented".

A PCV valve is a Positive Crankcase Ventilation valve that allows the excess gasses and pressure in the engine to escape so it doesn't destroy itself. Old engines used a Road Draft Tube that just vented the pressure and gasses to the atmosphere. After the EPA came on board, car manufacturers couldn't do that anymore, so they had to vent the gases/pressure some other way. The Chevrolet system uses a PCV valve and a hose that allows the gasses/pressure to leave the engine and travel into the carburetor, where it's burned in the combustion cycle. There's also another hose on the other valve cover that goes to the air cleaner. (see both the PCV side - numbers 8, 9, 10 and 11, and the Air Cleaner side - numbers 11, 14 and 16 in the example below)

What you have is basically a vent that allows the pressure and gasses to escape to the atmosphere. Not "correct", nor is it legal in the strictest sense, but it works.

If you're "restoring" the car, then yes, you should install the PCV valve, the rubber hose going to the carburetor and the proper clamps. All are available in reproduction.

Ed

[Nigel]

Hi Ed, Many thanks for your message and explanation, I will check to see if the cap I have is vented. Best regards, Nigel

[ko-lek-tor]

Ed, I am guessing auto correct on your device is changing it to PVC (PolyVinylChloride)? As knowledgable as you are, I am confident you meant PCV in each usage in your post? Just to keep down confusion.

[x66 714]

I used to work for NAPA years ago. I went to ACE hardware to buy a PVC valve for those who ask for it instead of a PCV. You can imagine the looks I got when I put that on the counter
...Joe

[bertfam]

HAHAHAHAHA. Yes, PCV so I've corrected it.

Thanks guys
Ed

[Nigel]

Hi Ed, Just to clarify as well I did mean PCV valve.

I checked this morning and the left hand side valve cover PCV valve hose runs to my carburetor and the right hand side valve cover has the Edelbrock vent.

I had a look online and it appears that the correct PCV Valve for the L48 350 SS (with correct Rochester 4 barrel carb) is GM part no 6421972 (CV679C) however I would be grateful if you can confirm this before I go ahead and purchase one.

I also checked the air cleaner which has a rubber bung in the back. Is there a special fitting which goes into the air cleaner or does the hose just attach directly to the air cleaner once the bung has been removed?

Many thanks in advance, Nigel

[bertfam]

No, the one you need for a 68 350 is P/N 6423695 (CV736C). Ebay has them ranging from several dollars to several hundred, but you can get the equivalent at Rock Auto (P/N V158) for just over a dollar!

The left and right sides of the car are designated by sitting in the driver seat looking forward. In other words, the steering wheel is on the left side, the clutch and brake pedals are on the left side, etc... (unless you have an export car with everything reversed!!)

Therefore, the left (driver side) valve cover should have the PCV valve and hose going to the carburetor, and the right (passenger side) valve cover should have the hose going to the air cleaner. I'm not sure what you mean by a "bung", but if you look at the picture above, you'll see the connector on the back of the air cleaner where the right side (passenger side) valve cover hose (number 16) goes to.

Ed

[Nigel]

Thanks Ed,

To clarify, the left hand side (drivers side) valve cover has the Edelbrock vent and the right hand side (passenger side) PCV valve hose runs to my carburetor currently.

I understand that the passenger side hose should run to the air cleaner and the drivers side hose should run to the carburetor.

There is currently a rubber stopper in the back of the air cleaner. If I remove the stopper I presume I need to purchase the correct connector to go into the back of the air cleaner. The hose will then attach to this connector.

Thank you for confirming the correct PCV valve for my engine, I really appreciate it. Unfortunately I am in the UK so no Rock Auto but I will track one down.

Kind regards, Nigel

[bertfam]

To clarify, the left hand side (drivers side) valve cover has the Edelbrock vent and the right hand side (passenger side) PCV valve hose runs to my carburetor currently.

I understand that the passenger side hose should run to the air cleaner and the drivers side hose should run to the carburetor.

Yes, that's correct for both.

There is currently a rubber stopper in the back of the air cleaner. If I remove the stopper I presume I need to purchase the correct connector to go into the back of the air cleaner. The hose will then attach to this connector.

If you mean a rubber plug to plug the hole in the air cleaner, then yes, you'll need to remove that and purchase an AIR CLEANER BREATHER, original GM P/N 6484966 (AC P/N FB59).

Ed

[Nigel]

Thanks so much Ed, I really appreciate your help and knowledge. I have found both the air cleaner breather and the air cleaner to valve cover hose online at Heartbeat City Camaro. Kind regards Nigel

[Nigel]

Hi Ed, I have just gone to buy the PCV valve GM 6423695 however Heartbeatcity camaro are saying that this is for a big block engine,  see link

https://www.heartbeatcitycamaro.com/store/product/13705/1967-74-Camaro-BB-PCV-Valve-396-427-454-GM%23-6423695-AC%23-CV-736C/

I just wanted to double check with you before I purchased it. Kind regards, Nigel

[x66 714]

http://www.gmpartswiki.com/getpage?pageid=49530

Read here...Joe