If it is the reluctor type, then you could get a DRAC/VSSB box from an early 90's full size truck, modify it and then wire it up to a stock S10 electric speedo cluster. Bonus points if you get one of those Blazer digital clusters.
https://www.tradecraftspecialties.com/DRACmodule
https://harristuning.com/Tbi/vssb-drac-calibration/
