Speedo codes

[fredp]

I'm in the middle of cleaning up and rebuilding an instrument panel to replace the one currently in my e9 and I've been stumped by the codes on the back of the speedo.
On the back of the MPH speedo coming out of the panel are the following code numbers -

2.71 W 1.14
20/134/2

and on the back of the KPH speedo that I want to install

4.72 W 0.68
20/134/5

Can anyone help with what the codes mean and how they relate to the setup of the car? Do they relate to the diff ratio?

Thanks in advance.

 

[pmansson]

w=0,68 is for a car with a 3.25 diff

and a speedometer in Km/h.
w=0.69 is the same but for slightly different tyres. The early coupes had 175 tyres, which was replaced by 185s around 1972 or so.
I use 205 tyres (with 70 profile as in the above examples) and remain with that speedo, with very little noticeable difference on the speedo.