Anti Surge Valve?

I need to make changes to my '57 truck to prevent fuel vapor from exiting the tank. I'm looking for an "anti-surge" or overfill protection valve to install in the filler hose (not the vent). If a vehicle has one of these valves you can usually see the green or white "ping-pong ball" in the fill path somewhere when the tank is dropped. Does anyone know of an application with this in the filler neck? Or does anyone know of one that installs inline? I seem to remember seeing one on a marine site but I can't find it now. I can only locate the valves that install in the vent hose. Finally, if someone has one sitting around they'd like to get rid of that could be an option as well.

TIA

in the sales literature for the 1995 monte carlo(i collect odd things), it specifically mentions it.

http://www.lov2xlr8.no/brochures/chevy/95mont/9.html

hard to read, but in the bottom right, "the innovative fuel filler" section.

That's it. Now to find one...

shouldn't be too hard, the junkyards here are FILLED with W-bodies. i'm not sure if it started with the 88-up W-bodies, but at the very least, the 95-up monte carlos should have it. i'm not sure if the onboard vapor recovery stuff that was implimented in ~98 or 99 on other W-bodies changed it or not though.

It's really tough to get time to get to a wrecking yard but that's probably going to be the only way to get one cheap.

considering on rockauto, they cost more than the tank itself..... not sure how that happens.

That's part of the reason I was asking for applications. I'm hoping to find an inexpensive filler neck without checking each and every part. Pricing on filler necks seems to be a percentage of OEM. Disappointing, really.