I found s couple of parts from png technologies. Haven't installed them yet, but these are them...halfway down...
http://m.pngtechnologies.com/?url=http://www%2epngtechnologies%2ecom%2f#2676

Sent from someone's plumbing

> On Mar 15, 2017, at 21:29, Roy Nicholl <RNicholl@NBNET.NB.CA> wrote:
> 
> Up here, propane filling stations are not suppose to fill tanks with conventional or Auto Stop valves … some still will, but more and more will not.
> 
>>> On 15-Mar-2017, at 21:51, The Bus Depot <vanagon@BUSDEPOT.COM> wrote:
>>> 
>>> What's the best place to look for one?
>> 
>> The original Westy tank was designed to take an Auto Stop valve, which had a safety feature that prevented the tank from being overfilled without user intervention.  Unfortunately Auto Stop Corporation went out of business years ago and the valve is no longer made.  A conventional fill valve can be fitted instead, and is generally available at RV dealerships or propane specialists. You would also need a manual bleed valve to screw into the bleeder connection next to the fill valve, and of course make sure to use it when filling. (If you already have a separate valve there, someone probably converted it already.)  As I understand it, technically a shop is not supposed to replace an Auto Stop valve with a conventional one because it defeats a safety feature that the tank was designed to have, and overfilling a tank can be extremely dangerous. (Our new replacement tanks are designed to accept a conventional valve, and that is what they come with.)  That being said, it is a relatively common modification.  
>> 
>> Ron Salmon
>> The Bus Depot, Inc.
>> www.busdepot.com