67-72 Chevy Truck fuel gauge diagnostics 101

[Sparkys66]

Hi guys, this is my first post and the fuel gauge in my blazer is driving me nuts.

I purchased a new gauge and sender for the blazer and did all the testing shown on page 1 of this post. Everything was spot on with the readings so I decided to go ahead and hook everything up while on my bench. at .8 ohm's the tank read empty. as the ohm's increased the needle on the gauge started to move, but once I raised the float arm to 1/4 or 22.5 ohm's the needle was already on full. If I lift the float arm anymore than 1/4 tank the needle continues past full. The sender reads true and so does the gauge. The other bummer is I had to install everything in the blazer so I could not only use the vehicle but know when to get gas. when the needle starts to drop below full, I find a gas station quick. any ideas would be great.

Mark