This is for a 67 with a console and after removing the radio and looking at the schematic I don't see a dedicated ground for this radio in the wring harness. Does the radio antenna work as a ground for the radio ? My radio worked before removal but had issues but not any that would make me think ground, one being when the radio was installed my tach worked at 80% of normal but did work, with the radio removed tach works normally and the radio bench tests fine.