I have the exact same problem...
In reading another post, it looks like this '70 owner also had this issue and 'fixed' it by sticking a resistor in line w/ his sensor
http://forums.maxperformanceinc.com/...emp+sensor+ohm
Two questions, does anybody know any sort of base resistance for the temperture sensors (80 ohms at 190?) and second has anybody had a real fix to this issue other then use a mechanical sensor or haphazardly stick a resistor in line w/ the temp gauge until you're happy?
Aaron