The Stovebolt Site Forums The Shop Area Engine Shop WC T-5 analog speedo

Jeremy:
I would check on inliners.org

They have extensive write-ups on T-5 conversions. I think they also cover your issue. Alternatively, there is an add on device to handle this, but it is a bit pricey from what I remember.

I hope this is helpful.
Regards,
STeve
New Orleans