Hi there,
There has been at least one good topic about the calibration and identification of speedo / speedometer ratios respecitvely matching to differential ratios, e.g. this one:
viewtopic.php?f=3&t=186&p=888&hilit=spe ... 282bb#p888
I found it a very useful information but more focused on speedo serial no. to the related details.
Maybe for easy reading it might be helpful to list only the coding reference on the speedo relating to turn per mile (tpm) or turn per kilometer (tpk) and the related differential ratio?!
Miles speedo (tpm):
1312 --> 3,54 diff ratio
1216 --> 3,31 diff ratio
1120 --> 3,07 diff ratio
1080 --> 2,93 diff ratio
1020 --> 2,88 diff ratio
Kilometer speedo (tpk)
820 --> 3,54 diff ratio
760 --> 3,31 diff ratio
700 --> 3,07 diff ratio
678 --> 2,93 diff ratio
638 --> 2,88 diff ratio