I hope you guys are aware the frame of the navigator L is literally a f150 frame and sits on top of the frame exactly the same way and f150 does. Extra leg room does not matter and does not change anything from the top of the frame down. Go under and look for yourself, the only difference is the suspension causes the navigator to sit lower, everything Else is nearly identical save for extra wires and what not that most can be moved around. There is no reason why ford doesn't allow a 35 gallon tank for the navigator L except for "not enough demand" but a f150 tank is pretty much interchangeable
