1966 JG question - PCV valve label for 427

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

Does any one have a picture of this beveled - one line of text valve?

Just off hand - the text would have to be real small to go around in one line...

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

David, I have found pictures of the 691 valve with both one line of text and two, both machined metal.

Nothing thus far, on 736 valves in this configuration.

[David L.]

Re: 1966 JG question - PCV valve label for 427

David, I have found pictures of the 691 valve with both one line of text and two, both machined metal.

Nothing thus far, on 736 valves in this configuration.

Ron,
Just the "691" valve? What about the "691C" valve?
Dave

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

David, both are the 691C, I have not seen a 691 valve without the "C".

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

David, If we do not get a good contribution perhaps we need to start a new thread - sorting out the 66 67 first design and second design PCV valves...

Here is what I have been mulling over these last couple of months:

Per the asy manuals we only have one part break point, 11-18-65, and that part continued for L36 and L72 in 67.

Why - for both years in the early parts books, as well as those from the early 70's do we have:

66 - 67 (427) 1st design
66 - 68 (427 spc hi perf 2nd design) Sp HI perf = L72

??????????????????????????????????????????????????

The AIM does not break out L36 and L72 - and only has this one record of change, so why do all the parts books carry over this 1st design and 2nd design into 1967? Moreover why carry it into the subsequent years' editions?

This must mean that there WAS a difference in SOMETHING that caused for these separate line items.

***

Does this have anything to do with California emissions and A.I.R. cars?
Everything on the top of the motor dressings are different, air cleaner, all the brackets, hoses - pcv hose too - why would it NOT be different?

***
Or since K19 shows as being used with L36, the L72 broke away from that base design?
***
On the L72 carb, is the vacuum port different such that it required - or they thought at the time it required non continuous valve function? For example, does this valve close (non C function) when under hard race type acceleration?

***
1st design and 2nd design can meant two things from the parts we have seen:

1. Functionality - C=continuous or Non C.
2. Mfg technology - some fully machined with later parts hybrid and even later fully a stamp-tube construction.

These are my thoughts:
Perhaps L36 and L72 BECAME different and this was just missed in the AIM.

66 up to the break point 691(solid steel)
66 after the break point AND 1967 - L36 - 691C (potentially later on part solid/ part stamped)

66 after the break point and 1967 - L72 - 736C (construction _?_) where by 1969 this valve was the thin metal stamped version, 1 5/8, and later in the 70's or 80's shortened to its current configuration.

[David L.]

Re: 1966 JG question - PCV valve label for 427

Ron,

I have owned a few original & NOS big block PCV valves ("solid steel" CV691 from a 1965 and NOS "stamped steel" CV-691C in 1967 & 1968 AC boxes) which I sold years ago but made sketches and notes about them before I sold them. I have done a lot of research on PCV valves with all my many vintage Chevrolet parts catalogs along with the assembly manuals. For the details that you are looking for you will need a survey of 1966-67 Corvette 427 owners with original engines. Starting a new thread is probably the way to go but I doubt that you will get much responce. I think that you should modify the title as follows "sorting out the 66-67 427 first design and second design PCV valves".

Dave

[Larry T.]

Re: 1966 JG question - PCV valve label for 427

I hope it is okay for me to get back to one of the original trains of thought in this thread.

Is there anywhere to get the "CV 691 C" labels in orange with white lettering per the most recent 1966 Judging Guide? I would not mind having some made, but I would not know what it is actually supposed to look like since I do not have an original. Is there anyone that could share a picture and possibly a scan of an original? If so and I can succesfully have some made I will share a few with you. My car is an early November 1965 production date, so I am certain the CV 691 C would be correct.

Thanks.

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

Larry - it is still valid. We will need to know this answer too!

I'll send you the contact info for the guy that a few of these made. But I don't know what he thinks about this, I sent him a note earlier.

[Larry T.]

Re: 1966 JG question - PCV valve label for 427

Larry - it is still valid. We will need to know this answer too!

I'll send you the contact info for the guy that a few of these made. But I don't know what he thinks about this, I sent him a note earlier.

The only other approach I can think of is to get a printer to identify the font and reproduce one as the current reproductions are made, using the same stock, just changing the numbers and color of print. If these things are that scarce maybe no one will be able to tell the difference. Who knows, maybe it would come out perfect.

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

Larry, send me an email later, the one I had for you bounced back, I have a picture or two at home, this is not as simple as described.

[Larry T.]

Re: 1966 JG question - PCV valve label for 427

Ronald, I sent you an e-mail, let me know if you did not get it.

Larry