The sender could be good or it could be bad but... I can get one of those in a heartbeat. We checked the gauge and we know that it will not work even with a good sender. The gauge is "bad". Any suggestions on where to find one? And thanks again for your interest.
Try Orlando Mustang, www.orlandomustang.com, Pete seems to have all sorts of hard to find things for Shelby's. He found me a replacement amp gauge for the 67 GT350, NOS in the original box. His phone number and current up to date parts list is on his webpage.