Hello there C3 experts,

IF it is for your '78, it will be(should be) non-vented. GM did offer locking caps as accessories from the dealer, but not all of the ones the dealer sold were in fact GM supplied. Most dealers would just get them locally from a parts house.
There should be something on the cap indicating if it is vented or not, but there may not be. I would venture to say that any cap made for a thread-on type fuel tank would be non-vented, per EPA regulations.


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Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

That would be really neat if it is a GM gas cap..they ussually don't last that long..the lock part that is..if it still works as I assume it does I would treat it to some old fashioned graphite in the lock mechanism..keeps it moving..what a find that is.
Rich

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My first parade at Carlisle 2010