The posts above have great info on troubleshooting & fixing what could be the problems indicated by your gauges, but if you want to be absolutely sure the problem is not with the gauges, maybe want a cosmetic restoration of the gauge faces at the same time, and are afraid of screwing-it-up by doing it yourself -- then using a professional service is not a bad way to go.
A few years ago I needed the speedometer repaired/restored for my '67 Mustang, had a very good experience with D&M Restoration (dandmrestoration.com) -- I was even able to talk with the tech who did the work when I asked over the phone what exact repairs they'd done. Be forewarned it takes a few weeks, though -- the turnaround for my speedometer was 2 weeks but that was November/December, which I was led to believe is a slower period of demand for their work.
A few years ago I needed the speedometer repaired/restored for my '67 Mustang, had a very good experience with D&M Restoration (dandmrestoration.com) -- I was even able to talk with the tech who did the work when I asked over the phone what exact repairs they'd done. Be forewarned it takes a few weeks, though -- the turnaround for my speedometer was 2 weeks but that was November/December, which I was led to believe is a slower period of demand for their work.
