I have a fuel guage that is reading backwards. I was informed by the manufacturer of the guage that I need a 0-90 ohms sending unit installed. I currently have a 90-0 ohm unit. My mechanic claims that the 0-90 sending units will not properly fit in my tank (I have a stock tank in my 66). The manufacturer of the guage said there are conversion units I can buy and place between the sending unit and guage to make it work properly. Can someone point me to those conversion units? Thanks