Fitting the 912iS sensors to an exhaust

I'm installing a 912iS in place of a 912ULS and need to modify the exhaust to accept the 912iS temperature sensors.  The sensors have a M14x1.50 nut (I think) so I have to add M14x1.50 male thread stainless steel bung.  It looks like the sensors are a bit long for the diameter of the exhaust pipe, so I need a standoff of maybe 1/4 to 3/8" as well.  Does anyone know of a source of male SS weld-in bungs?  Or have ideas on an alternative?