gas caps

[dvonk]

it says in the Chassis Service Manual that the 1958 Buick does not need a vented gas cap because there is a vent tube on the gas tank itself.

would adding a vented gas cap change the fuel system in any way, either beneficial or detrimental?

[Smartin]

Why would you use a vented gas cap when the tank is already vented? I don't see any problem with doing it, but I'm curious. Having trouble finding an original cap?

[dvonk]

im looking at perhaps getting a vintage aftermarket locking gas cap... many of the ones ive seen on eBay are vented. i was just curious if the redundant venting would have a deleterious effect on the fuel system.