Thanks for the info. I just got off the phone with a friend that had his cluster rebuilt by Instrument Specialties. $$$$ After installing it the gas gauge read 3/4 when full. He had a new tank and sender so all should be good. He was told to ground the sender wire and if the gauge reads full the gauge and wiring should be good. Hook up the sender out of the tank and do a sweep. If it goes from empty to full the sender should be ok and the problem is in the tank. They shorten the float arm by a 1/2" and it then works properly. Either the float is hitting a baffle at 3/4 or the arm isn't the proper length we don't know. I am just repeating what was I heard. Joe said he tried a known good original sender and had the same problem.