I installed a petcock in my oil supply line to stop a wet sumping issue.  I know the dangers of doing this - I have a detailed pre-ride checklist and am confident I won't be starting the engine with the oil supply turned off.

I purchased a custom-made brass petcock from overseas, and was not thrilled with the small orifice (11/64") nor the choice of fitting on the bottom end.  If anybody can use this, contact me and we can make a deal.

I found a different petcock manufactured by Nibco that allowed me to use stub fittings at the tank and pump (sold by Randy Walker), and then simply solder the petcock to those fittings and run 1/4" copper tube for the oil line.  It was simpler for me, and the orifice is a full 19/64".  Working well so far.  I obviously made a different handle for it.  I bought several of these as they appear to be obsoleted by the manufacturer.  If anybody wants one for $15 plus actual shipping, please contact me directly (lindbergjohn@hotmail.com).

Pictures attached of the brass petcock, the surplus petcock, and one installed on my '29.