The stock lower water pipe is beaded to help keep the lower heater hose from slipping off. As far as I know I have not seen anyone attempt to flare the OEM steel pipe. Typically people have a bung welded on to the pipe instead. I do not know how well that steel pipe would accept a flaring tool. 37* JIC I assume?

Here is a picture of one of Dougie's motors - you can see how his SS lines are routed.