When I fill up the tank Im talkin all the way to the rim my guage only reads a little over 3/4 of a tank. Also the hand floats realll bad if its on a half tank and I hang a corner at any kind of speed it will float one way or another depending on which way I turn 1/4 of a tank. I have a 97 z28 lt1. Thanks

 

It's normal for the gauge to move up and down a bit when you make a turn, brake or accelerate. But it's not normal for it to indicate only 3/4 when the tank is full. It's more normal for the gauge to indicate way above full, and to stay there until you have used up 3 or 4 gallons.

If you feel you have problems with the gauge, Shoebox has the best reference:

http://shbox.com/1/4th_gen_tech2.html#fuel_gauge