86 fifth ave fuel economy, how much do you get to a tank?

Just wondering what anyone else is getting to a tank of fuel, I can fill this one with about $70 of fuel but it does not seem to be getting very far, right now the gauge is at just under half and I have just over 100Km's on it....I know it is a V8 but still...should not be that bad. I am hoping the gauge is just broken, will fill it at 250 or so and see what it takes to refill it, but thought I would ask.

filled it at E with 225Km's on it.....$65 worth....getting like 10 MPG.....but the car is running just fine....engine wise.