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Vented or unvented fuel cap ?

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Old May 9, 2002 | 05:31 PM
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Default Vented or unvented fuel cap ?

Hi
I'm looking for a locking fuel cap for my 68 .
It's a big block car with single fuel line, the cap presently installed is a vented cap.
Somebody offered a locking cap, but he thinks it's a sealed cap.
Are all 68's suppost to have vented caps, or does this depend on engine type originally installed ?
Do I have to install a vented cap ?
Thanks Gunther :seeya
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Old May 9, 2002 | 06:12 PM
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Default Re: Vented or unvented fuel cap ?

Gunther,

A vented fuel cap is correct for your 1968 Corvette regardless of which engine was originally installed.

I don't have the part number handy (I'll edit this and post it later), but I can tell you that it is still available from GM as I recently purchased several... The only difference between the current service part and the original cap that was on your car (that I'm aware of) is that the original cap used a cork gasket for sealing while the service cap uses a rubber gasket. You'll never see the gasket when the cap is installed, but at least one aftermarket vendor sells the correct cork gasket for those so inclined.

Regards,
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Old May 9, 2002 | 06:34 PM
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Default Re: Vented or unvented fuel cap ? (Rowdy Rat)

Thanks
Do you say that GM is selling a original locking ( with key ) fuel cap ?
Early C3's had a big size tank opening, about 3 ".
Corvette central has discontinued them already.
Paragon still has 70 style avail, but unvented.
They claim that you can drill a hole to make it a vented cap.
Is this so easy ? What's about fuel spillage ? What size hole where ?
Gunther :seeya
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Old May 9, 2002 | 11:33 PM
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Default Re: Vented or unvented fuel cap ?

Gunther,

The fuel cap that I referenced was the standard (non-locking) vented cap... Sorry for the misunderstanding. The part number for this standard cap is 3952708. I am unaware of anyone selling the locking version of the vented fuel cap that was available as a dealer installed option.

Paragon is a first rate vendor and I'd be willing to bet that what they told you is correct. If you wish to go that route, I'd ask them to send along very detailed instructions on how to accomplish the task.

Chevrolet added a vent to the fuel tank during 1969 production (sometime around July-August 1969) which eliminated the need for the vented cap. Regardless, most (if not all) 1969 Corvettes used the vented cap through the end of the 1969 model year... For the 1970 model year, Chevrolet went to a sealed cap.

Like Chevrolet, you can use either cap on a vented tank, but I would not attempt to use the sealed cap on a non-vented tank... Vented only.

Regards,
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