Just went with what Tony says. I would have used a shorter nipple up top after seeing how high it is but in thinking it through getting the valve cover off might be possible with the ball valve higher so it will stay.May think of using steel fittings for the bus heater. Especially the long nipple. I seem to remember issues with fatigue cracks with brass/bronze.
Gasoila. I have never had a problem and works well for me.xbskt - What are you using for pipe dope on your heater hose fittings? This past weekend I replaced all my hoses to hot water & bus heaters because the old ones developed pin hole leaks all along them; never seen that before.