Your lines need to go from the transmission fittings to the fittings in the rad. If your rad doesn't have the fittings, then you'll need to mount a quality external cooler. The optimum location for the external cooler is in front of the rad. 18" of line is far to short. Steel brake line will work just fine, all you have to do is bend it to fit your application. I also think there is a company that makes cooler and fuel lines for a wide variety of vehicles. Can't think of the name, but google it and see what you come up with.
transman