Hey again, recently posted a topic but have since figured that issue out so I'm onto the last main issue I've had with my car. I am just about done with my rwd swap on my 93 Subaru legacy, no fluids in everything, new clutch, flywheel, and every arm I could buy. The one issue I've really had with the car has been driveshaft and gas tank issues. The driveshaft is currently getting rebuilt so that should be solved in the coming days and one of my issues with the gas tank was a bad fuel pump. The other issue I'm having is no gas gauge. I know that the fwd tank only has the one plug because it doesn't have the middle separating hump for the driveshaft and that the awd tanks have a second plug for the syphon and to get the fuel gauge correct. While I do have the plug I was wondering if its as simple as splicing into the wiring for the main plug and that'll work or if I have to add some wiring directly to something else. The car is totally drivable and honestly as long as I go to the gas station like every 2-3 days I should be fine but id like to have the piece of mind of knowing exactly how much gas I have. Hopefully you guys can help me out!!

best bet is start comparing wiring diagrams.. you can get pretty much everything you need here: http://jdmfsm.info/Auto/Japan/Subaru/

on average, between 250-300 miles a tankful is typical (without running out) - depending on driving style, terrain, etc,

Yep, the two float assemblies are wired is series.

VERY IMPORTANT - The main float assy. unit (the one mounted with the fuel pump) MUST be the one for AWD  for the fuel gauge to read correctly when wired with the sub unit. The FWD unit has a different resistance value.

Example: I'm going to use made up numbers here. Both AWD and FWD use the same fuel gauge. The fuel gauge is supplied voltage and the other side of it is looking for a ground through the variable resistor of the float assy. The gauge will show Full at 0 ohms and Empty at 100 ohms.

FWD one float assy. measures 0-100 ohms.

AWD with two float assy. each will measure 0-50 ohms and hooked in series will measure 0-100.

When you hook two resistors in series, the ohm value of each is added together for the  total value of that circuit.

In case you don't know what series is, when you put batteries in a flashlight, you are hooking them up is series.