Eunos Roadsters can only be converted in 4 ways:
1.Fit a UK spec speedo, straight swap
2. Fit a calibrated face, usually calibrated to 110 or 120mph, rather than factory 140mph
3. Add sticker marks to the speedo, this was the old school approach. If you didnb’t know your kms, you couldn’t read the speed at night. Technically not a MOT failure because there is no need for a mph speedo
4. Fit a geared mechanical converter incline to the speedo cable.
No such thing as an electronic conversion of the Eunos Roadster as the speedo was purely mchanical.