You have photos of the vintage air??If I'm reading this right, your talking about the power steering pump on the motor? If so, you can cut the neck down on the stem of the pump and braze a bung on there. That's what I did to convert my pump to AN. See link attached for fittings. Not sure of the size tho because I did it awhile ago.
Or you can use a Racetronix fitting with the olive that you can crush onto that stem if there is enough room. I used this on my Vintage Air heater to convert it to AN, and it works awesome.
View attachment 332067
I have a good used pulleyanyone have a new pulley laying around? and or a suggestion on which one to use? not against going aftermarket or some type of shiny stuff. eventually ill do some measuring and buy a nicer one. next couple of weeks i should be putting this back together and doing a nice write up for everyone.