Classic/Antique Car Repair: 66 Mustang guage problem, oil gauge, speedometer

Question
I just purchased a nice 66 mustang.  Instrument gauges are not working right.  Gas reads between 1/2 and 3/4 when full, temp, oil and voltage needles are all to left.  when I tapped the temp and oil gauge faces, the speedometer jumps slightly (about 5 mph) when car is running and in drive.  am I looking at a panel problem, or a coincidental individual problem with the gauges? Speedometer reads pretty good by a check with another vehicle driving at the same speed.

Answer
Hi Charles:
This is normal on a car that age. Old analog gauges are known to give false readings as they age. You really have two options, but first, check to make sure the battery is of the right voltage for that vehicle. If the battery is not powerful enough, it will cause false reading on gauges as well. Not sure, but your battery should be putting out from 45 to 60 cranking amps depending on the options on the vehicle. If the battery is of the correct size, then your two options are...

1. Have the instrument gauges recalibrated (very expensive)!
2. Just live with the false readings, as you know the correct ones.