Thanks for the input guys.
So what exactly is it that fails inside the gauges? It can't be rocket science to figure out a proper fix.
i.e. What exactly did AutoMeter do that fixed the small gauges?
The short story.... with a few "allegedly's": Ford had originally subcontracted the gauges to Autometer and the gauge control module to a different company. When gauge failures started to appear, a LOT of finger pointing started to occur - and likely continues to this day. Autometer CONTINUES to insist the failures are not the fault of their gauges. As their proof, allegedly they have some kind of other application using the same internal design - and with superior reliability. The maker of the original Ford GT gauge control module (another "suspect" according to Autometer, is no longer in business.)
All of the
original gauges use an air-core design for the needle movement of the gauge. Eventually, an agreement was struck between Autometer and Ford where Autometer re-made all of the small gauges using a more conventional stepper-motor design. (Ford most likely generously funded all or most of this re-do.) The appearance of these gauge is IDENTICAL to the originals - same case, glass, face, needle, etc. To the best of my knowledge, there has never been a failure of one of these replacement gauges - available exclusively from Autometer.
Allegedly, Autometer did not believe that their stepper-motor/electronics design could accommodate the faster needle-movement requirements of the speedometer and tachometer. These two gauges were never recreated and are only available as OEM through Ford - or in an aftermarket design/form factor (aka, smaller) through Speedhut.
DBK can correct me if I am grossly in error of my understanding of this history.