Fuel tanks??

Question:
On a 1987standard kit built RV-4, what type of venting would the tanks have?
1.Neutral pressure ?
2. Vacuum ?
3. Pressurized ?

I'm going from resistive to capacitive (in line) senders from Belite to mate up with a Belite dual 2 1/4'' fuel gauge. The Belite tech rep said that his senders only work accurately with vents that have neutral pressure, and that if mine don't, then I would have to replace my bad/inaccurate ones with the orig. Vans type resistive senders....which I would rather not do

Thanks in advance for all help.

Would you please explain why a difference in air presure over the fuel would make a difference in how capacitance reads? Not implying I don't believe it, I just don't understand it. I have capacitance fuel level on my tanks with the Dynon converters.

Are you sure they are capacitive senders? Belite makes some senders that sense the pressure at a location in the fuel tank to determine fuel level. These pressure-sensitive senders are sensitive to tank pressurization.

Neutral

The overall design would be neutral. Some may cut or modify the vent outlet by angling that could make it go one way or the other.