1966 JG question - PCV valve label for 427

[Ronald L.]

The 1966 JG on page 107 for 427 says "the white printing" on the label...type CV 691 C AC Spark Plug.

Is this the correct number?

- all the big box stores have black lettering with one shop having white letttering - but they all are a 736C type valve. Is the 691 label available if correct?

[Rich P.]

Re: 1966 JG question - PCV valve label for 427

Ron,

check LICS I think they have the white 691 tag

Rich

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

Rich, that is one place I did look, their white label has 736, not 691...

[Rich P.]

Re: 1966 JG question - PCV valve label for 427

Ron, your right LICS just has the 736 valve lable. Now that I think about this I remember finishing a BB several years ago and my customer got 2-3 special made 691 labels. I remember because he had a original one to go by. I am suprised that they still don't make these. Maybe someone else might know of a source,

Rich

[David L.]

Re: 1966 JG question - PCV valve label for 427

According to my vintage 1966 & 1967 Chevrolet parts catalogs the CV-691 PCV valve (GM # 6421981 in GR. 1.745 ) was used on 66-67 Pass., Corvette (427) (1st Design) exc. tri. carb. The CV-691 PCV valve is machined steel (not stamped steel). The later version CV-691C PCV valve were part machined steel but mostly stamped steel. The "C" designates constant action. I once owned several NOS CV-691C PCV valves in boxes dated Aug. 1967 and Jan. 1968. The CV-691 valve that I once owned was from a 1965 Chev. w/ orig. 396 engine.

The CV-736-C PCV valve (GM # 6423695) was used on 66-67 Pass., Corvette w/S.H.P. (427)(2nd Design). This valve is entirely stamped steel.

GM # 6421981 was replaced with GM # 6423695 in July 1969 as per Chevrolet Parts history.

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

In inquiring who has the white round label, I was referred to Page F379 of the 66 AIM that shows an engineering change dated 11-19-65 where the valve part number changed from
6431871 to what is shown, 6423438. Please keep in mind my version of the book has bad print, but not the numbers above. In the AIM this shows for L72, is L36 not listed and different?

[David L.]

Re: 1966 JG question - PCV valve label for 427

In inquiring who has the white round label, I was referred to Page F379 of the 66 AIM that shows an engineering change dated 11-19-65 where the valve part number changed from
6431871 to what is shown, 6423438. Please keep in mind my version of the book has bad print, but not the numbers above. In the AIM this shows for L72, is L36 not listed and different?

My 1966 Corvette assembly manual shows part # 6421271 changed to 6423438 on 11/19/65 in the revision box (sym. #11). The part numbers for the PCV valves in the assembly manuals never agree with those in the Chevrolet parts catalogs. The only big block PCV valve shown in my 1966 Chevrolet Parts Catalog (Oct. 1965) is GM # 6421981 (CV-691). I assume GM # 6421271 is the 1st design (CV-691) and GM # 6423438 is the 2nd design (CV-736-C).

My 1967 Corvette assembly manual shows GM # 6423438 as the part # for the L36 PCV valve.
My 1966 Chevelle assembly manual shows GM # 6421271 as the part # for the L35 PCV valve (396 engine).

[Jaime G.]

Re: 1966 JG question - PCV valve label for 427

Try Paul Noble in Philadelphia.
He has the correct tag for the car.

[David L.]

Re: 1966 JG question - PCV valve label for 427

I sold Paul a NOS CV-691-C PCV (box dated 1967) valve back in October of 1993. He was also looking for the tags back then as well.

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

He does not show as a NCRS member any contact info?

[Jaime G.]

Re: 1966 JG question - PCV valve label for 427

He does not show as a NCRS member any contact info?

Please email me at jgesundheit@sandhillmgmt.com and I will give you his information

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

In reviewing this again, I get multiple opinions on what is correct.

Does the preceding discussion mean the 736C is the correct PCV valve for mid 66 and 67 L36 cars?

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

What is the understanding on 66 - 67 PCV valves?

[Bob J.]

Re: 1966 JG question - PCV valve label for 427

My 1966 Corvette assembly manual shows part # 6421271 changed to 6423438 on 11/19/65 in the revision box (sym. #11). The part numbers for the PCV valves in the assembly manuals never agree with those in the Chevrolet parts catalogs. The only big block PCV valve shown in my 1966 Chevrolet Parts Catalog (Oct. 1965) is GM # 6421981 (CV-691). I assume GM # 6421271 is the 1st design (CV-691) and GM # 6423438 is the 2nd design (CV-736-C).

My 1967 Corvette assembly manual shows GM # 6423438 as the part # for the L36 PCV valve.
My 1966 Chevelle assembly manual shows GM # 6421271 as the part # for the L35 PCV valve (396 engine).

Not to be picky but the 6421981 is a CV691C not a CV691.
Hope this helps,Bob

[Ronald L.]

Re: 1966 JG question - PCV valve label for 427

So by inference it is the 736-C that we expect to see on L36 for 66 and 67?