I have one of these in my 1986 F150 and it works great. It registers to 999,999.9 miles.
The price is quite good, especially on the 1st link.
https://www.ebay.com/itm/OEM-Instrument-Cluster-Speedometer-Gauge-E3HZ17255A-For-Various-80-86-Ford-Truck/332611131080?epid=1536784025&hash=item4d712b16c8:g:B2QAAOSwpFtaxkck
https://www.ebay.com/itm/NEW-OEM-1983-Ford-Truck-E3HZ-17255-A-Instrument-Cluster-Speedometer-Gauge-85-MPH/182905529474?epid=1536784025&hash=item2a9604e482:g:vOYAAOSwyGZaDgbs
This thread link is for 1965 - 1979 trucks, but may offer food for thought:
https://www.ford-trucks.com/forums/1492977-3-5-ecoboost-pretty-much-a-direct-bolt-in-to-any-65-79-truck.html
Hmmmmm…. I am normally very prudent, but in a state of weakness , I bought this. Perhaps, sometime in the future, a thread will be begun regarding installation?
For others who might like to see this, it will be at the Garagemahal Truck Show.
Since you have a 6 cylinder [me, too!], I will share that I have had excellent results with Motorcraft SP452, which is for the later fuel injected engines.
https://www.oreillyauto.com/detail/b/platinum-5897/ignition---tune-up-16776/spark-plug-12874/b14eb31b13d7/motorcraft-platinum-spark-plug/sp452/6231885/1995/ford/f-150?q=spark+plug&pos=2
I have a MSD 6AL box and set the gap @ .050".
Yeah, I said that about Big Blue. And now I have the RSK stuff, the front receiver, and the step brackets to powder coat. And several parts under the hood to clean, if not powder coat.
Onion layers???
I wonder if this would work?
https://www.ebay.com/itm/OEM-Ford-Mustang-Truck-Fairmont-Leather-Sport-Steering-Wheel-1978-1979-Button/143354445085?hash=item2160973d1d:g:oiMAAOSwPdNdUd0Q
Well, you never get it [money] unless you ask! "What is in your wallet?"
https://www.ebay.com/itm/1980-1981-82-1983-84-1986-FORD-TRUCK-F100-350-BRONCO-SIDE-VIEW-MIRROR-PAIR/273966569219?epid=1411242080&hash=item3fc9ae1703:g:ThAAAOSwHKtdVFNi