I have got a true 67 GT. i put new gauges in the dash(fuel, temp, oil pressure). To do so I i had to do a little grinding on the back of the gauge cluster. It appears that I got some little metal shavings on the magnet for the tach. It’s not working at all now. I’m wondering if the shavings are causing it and if so does anyone know where to get a new tach that will fit in the gauge cluster? Thank you I’m advance for your help.