Converting a 203 to part-time

[milner]

Does anyone know of,or have done this conversion? I have a 79 K-10 Silverado w/203 Full-time transfer case. I am thinking about converting it over to part-time. I have heard w/MileMarker kit that you have to occasionally lock it in(not a big deal). I have heard that with a Doug Nash kit that you don't and that it is a better kit. Any suggestions? Anybody know of where one can find a Doug Nash kit,I have heard that they are still avalialble? Thanx in advance.