I tried some cable to digital stuff from Dakota Digital and ran out of patience trying to dial it in. My buddy still had a cable driven speedo but the 4L80e we swapped in needed a vss signal. I could never get it to read accurate to speed and shift correctly. I could get it to shift right but it was 20mph slow on the value to gps or the mechanical speedo. If I adjusted it to be accurate the shift timing was so far off it was annoying to drive.
I messed with it on multiple weekends trying to get them both to work right and ended up scrapping the Dakota Digital crap and we put a vss output on the 208. I need to finish the harness to swap in a ‘91 digital speedo cluster for it.