Frank Cnodelli's site has:

Regulator, horizontal 90 degree vent, 2 stage, Marshall  Brass 290, 1012-5
34.95

The one?

*bob
*
On Wed, Mar 17, 2010 at 7:33 PM, David Beierl <dbeierl@attglobal.net> wrote:

> At 03:52 PM 3/17/2010, courtney hook wrote:
>
>> So last summer all was well with my stock 77 Westy factory propane
>> tank/stove setup. This year I went out to give it a test, opened up
>> my tank valve, then went inside to turn on a stove ring. Nadda.
>> Nothing at that end. My regulator has a knurled ring that is spring
>> loaded (excuse my poor knowledge of this) that you can wind back a
>> bit, and propane hissed out from here. I wound it back down, (this
>> is NOT the on-off valve that closes the tank), to where it should
>> be, so there is propane in the tank, yet it does not get up the
>>
>
> Dear Courtney -- I've never seen a '77, but from your description I
> think that the knurled knob you're talking about is the manual vent
> valve on the tank itself or a vent valve on the auto-stop filling valve.
>
> To check regulator output, loosen a fitting on the  output of the
> regulator and smell for gas at much lower pressure than the tank.  I
> suspect the problem *is* the regulator, and you can replace it for
> ($30 or so ten years ago) from an RV place or online vendor.  It's
> made by Marshall Brass and someone else will have to quote the number
> as I'm having a senior moment.  If you still have the square one it's
> due for replacement with the newer round one which is an inch or so
> longer and involves bending the copper output tubes a bit.  The
> square one is NLA because of premature failures at the diaphragm corners.
>
> Yours,
> David
>