That's what I was afraid of; anything I could find about recalibration was for those years. Although since the speedometer is also off (any time I'm going under 35mph it bounces +/-10mph), that makes most of that dash cluster inaccurate, I might just take it out and use it as a template to build a fresh one out of aftermarket gauges. It might not be pretty, but it's had enough other atrocities committed to it there's no hope of it being brought to factory spec/show car status anyway.
I'm new to not just this thread, but Thunderbirds as well, but I just purchased a 1983 Turbo coup from my uncle...
However he had decided that the standard turbo 4 wasn't enough, and did his own engine swap. From what I understand, here's how the car is as it sits in my driveway:
-original 1983 body -V8 302 out of his friend's 1988 Mustang (wrecked the body but the engine survived) --That engine was supposed to have EFI but he couldn't figure that out so he put a carburetor on it. - he never adjusted the in-dash tach so he put in a Summit tach next the shifter (pictured)
Now, since the car was originally spec'd for the turbo 4, the tach in the dash reads double, so I'm constantly looking at redlining it, or I have to go out of my way to look at the Summit tach. Is there any way that I can recalibrate the tach in the dash, or is it set and the only option is replacement instead of adjustment?