If things go as planned I will have my newly constructed fuselage tank installed in my flying RV3 to use instead of my leaking wing tanks. Will do a weight and balance, calibrate the mechanical fuel gauge, and do a fuel flow measurement. My question is what paperwork or FAA involvement is needed? Plan to fly in pattern initially until system checked out. Not much plumbing changes required and nothing changed from electric backup pump forward to engine driven pump and carb. Tank is smaller than standard vans but identical otherwise.