Dad needed a unit for his 1970 Pontiac, those are very unusual units, made of unobtainium. We finally resorted to Bob's Speedometer Shop for a rebuild.

https://www.bobsspeedometer.com/1/120/index.asp

A bit spendy but when there's nothing else available...

Robert

'68 Fury Convertible
'69 300 Convertible
'15 Durango 5.7 Hemi
'16 300 S Hemi