[ERA Chas]

Dan---
Leave the 'real, original' Smiths speedo for the DB's in the parking lot to ooh and ahhh over. Drive by the tach.
Do the formula for MPH inputting your rear gear, 1:1 trans (4th) and tire diameter. Do it for each 1000RPM. Then just look at the tach when you're in the school zone for your sedate MPH.
Also do it for near redline.
For instance, 6200 in 4th with my combination was 155MPH. Which I enjoyed whenever space allowed............