Re: 580C Valve = 61-79 Ford/Mercury/Ford trucks

[Robert Jorjorian]

John, first off I have never seen or owned a 590 valve that could be disassembled and I've seen many.
The wrap around decal that is seen in the shop manual and other GM publications I doubt was ever used in production.The disc which was included in some NOS 590 valves in AC boxes has more credibility for being used in production.If you ever examine the white 63 FI car used in the R&T road test it appears to have what looks like the disc installed. Michael Hanson the foremost 63 expert is not sold on there ever being a decal or seeing what looks like the disc in the R&T magazine. The jury is still out on the answer to that question.
I'm still waiting to hear from the experts on what exactly the C designation on later 590 PCV valves actually means. I'm sure as soon as I or other members post the answer the board experts will imply they have known that info for a LONG time.

[John D.]

Re: 580C Valve = 61-79 Ford/Mercury/Ford trucks

Robert, It would be neat if we could find out if the free spinning decal was used on the 590's. I don't know what the c means. Could be an engineering change in that the 590 and 590C are constructed differently for sure. I have some other ideas as to what it could mean but no newsworthy. Good nite as its been a long day. Someday I will try one of those Ford PCV's on my white 63. They look the same don't they. I have enough of them that I could slice one done the center and compare the insides. But don't have time for that now. Thanks, John You new behavior is commendable.