427 Correct PCV Valve?

[Neil S.]

My 69 L36 has a Delco PCV Valve #789 c. I dont beleive this is the correct one for the car. am trying to locate the correct one, and if I cannot, I would like one that would be as close to stock as possible. I have gone through the archives and not found much information except that the aftermarket ones are way far out of spec. So does anyone know the right Delco PCV# or one that will work? Also my 427 has never idled right and am wondering if the valve I have in there now is somehow the culprit. Any suggestions?

[Joe L.]

Re: 427 Correct PCV Valve?

My 69 L36 has a Delco PCV Valve #789 c. I dont beleive this is the correct one for the car. am trying to locate the correct one, and if I cannot, I would like one that would be as close to stock as possible. I have gone through the archives and not found much information except that the aftermarket ones are way far out of spec. So does anyone know the right Delco PCV# or one that will work? Also my 427 has never idled right and am wondering if the valve I have in there now is somehow the culprit. Any suggestions?

Neil-----


The original valve was a AC CV-736C. That valve is still available today from Delco dealers or GM dealers under GM #6423695. The valve available today, although of original specs, is configured a little bit differently from the original valves. However, it should function perfectly. Only about 5 bucks from Delco dealers.

Also, the CV-789C you have installed is definitely not a correct valve. I don't know how its calibration differs from the CV-736C but I would not recommend using it. It was first used for the 1976 model year and its only Corvette applications were for 1989-91 with L-98.

Will this solve your idle problem? It might and it's worth a try but I suspect it won't solve the idle problem.

[Neil S.]

Re: 427 Correct PCV Valve?

Joe, what sort of problems could this valve create?

[Joe L.]

Re: 427 Correct PCV Valve?

Joe, what sort of problems could this valve create?

Neil-----


Actually, an incorrect PCV valve could create idle problems. However, I don't think that it will make much of a difference in your case. But, like I say, it's worth a try and you need to get a correct valve on there, anyway. For 5 bucks, it's a "no brainer".

Other problems which could be created are excessive oil consumption or oil leaks.

[Neil S.]

Re: 427 Correct PCV Valve?

Joe, what do I look for in the originals. I did a little hunting and dug up a few that are supposed to be original NOS for $9 ea.

[William L.]

Re: 427 Correct PCV Valve?

Neil
This a piture of my originalCV 736C PVC valve.
Bill

[Joe L.]

Re: 427 Correct PCV Valve?

Joe, what do I look for in the originals. I did a little hunting and dug up a few that are supposed to be original NOS for $9 ea.

Neil-----

If they're being sold for $9, you can almost bet that they're the current offerings. These are 100% functional but configured slightly different than originals. Actual original valves usually sell for Big $$$$; sometimes $500, or more but I think that the buyers are usually limited to "silly" people.

Over the years these valves have changed in very minor ways. I believe that original valves used during 1969 have "AC Spark Plug" embossed on the sides rather than just "AC". Also, I believe that the 1969-era valves had only 4 "indentions" around the base. I think that there's also a difference in the alpha character which appears on the bottom of the "plunger" inside the valve, but I've forgotten what the difference is.