'63 Corvette PCV valve 590 or 590C?

[G B.]

I've seen three versions of the #590 PCV valve: a black #590 with a short body, a black #590C with a longer body, and a silver #590C with the longer body. I think the short black 590 may be the only one used on early '63 Corvettes, but I'm not sure. Perhaps the 590C was used on late '63 or early '64 Corvettes.

Can anyone tell me the original assembly line application for the longer black 590C valve? I'm pretty sure the silver version that pops up on eBay is just a service replacement.

[Duke W.]

Re: '63 Corvette PCV valve 590 or 590C?

A silver CV590C was OE on my mid-production SWC.

Duke

[Loren L.]

Oct '62 Parts Book calls it out as 590,

part #5649689.

[Mike L.]

Re: '63 Corvette PCV valve 590 or 590C?

My early 64 fuelie has a black #590 and my friend is a orig. owner of a 63 fuelie and has the same one on his 28,000 mile car. I think the silver one's were service replacements.

[G B.]

Re: '63 Corvette PCV valve 590 or 590C?

Mike, just to be crystal clear, is your valve a black 590 or a black 590C? Regardless of the stamped number, are you very confident that this particular valve was installed on the '64 assembly line?

[Michael H.]

Re: '63 Corvette PCV valve 590 or 590C?

Jerry, I still have (somewhere) the original black 590 that came from 19,746 FI conv. I'm pretty sure the black machined valve was used through the end of 63 production and the silver plated stamped valve was later.

[Mike McKown]

Re: '63 Corvette PCV valve 590 or 590C?

Jerry:

I have two '63 units with the black 590 valve. Don't think they have ever been changed as I have had them since late '60's. Had two other units equipped the same way. Late '60's parts book shows the 590 for '63 only (Corvette). Other 283, 327 Chevelle, Nova and Pass cars, '64-'67 used this valve. No mention in the book of a "C" suffix valve. Maybe the "C" has something to do with California emmisions.

[Duke W.]

Re: '63 Corvette PCV valve 590 or 590C?

My '93 vintage Delco Valves and Filters catalog lists a CV590C, but not a
CV590. Most of the listings have a "C" suffix, but a handful do not. The handful of listings without the "C" suffix appear to be something other than conventional PCV valves from the style photos. One is a rubber grommet and several appear to be a small cannister, which mays function as a liquid vapor separator.

The style reference photo for the CV590C indicates a bright metal finish.

Duke

[Robert Jorjorian]

Re: '63 Corvette PCV valve 590 or 590C?

Jerry, I agree with Michael that the black machined 590 valves most likely are true 63 production parts,with the shortest version being the one most commonly found on original 63 cars.

There are 2 different sizes in the machined 590 valves with the first style being the shortest at approx,2 1/4 inches long verse the second style being the same length as the later 590C at approx. 2 9/16 inches long.
The 590C was made in three styles that I'm aware of.The earliest 590C's were made in a machined construction but they not very common. The second and third styles were unmachined versions with the crimp on the main barrel at either 1 inch or 1 1/4 inch up from the end of the threads.
The earliest NOS 590 valve I have seen is boxed in a 5/63 AC box.It is the short machined style with a circular grey paper ID tag that pushes over the hose end. If I remember correctly it reads "TO MANIFOLD SIDE" and "CV 590".It is not blackened but has turned or tarnished to a near black color over time.

[Peter L.]

Re: '63 Corvette PCV valve 590 or 590C?

Mike - I have several SERVICE part valves with boxes that read "VENTILATION VALVE" and "PCV VALVE." The "VENTILATION VALVE" boxed are dated '65 and '66 while the "PCV VALVE" boxes are '68 and later. All have the designation "C" after the AC P/N, e.g. AC CV###C; so I don't think it's a California thing; but I'm sure we can find some other thing to hang on the CA folks. Pete