Speedo Calculator

[mk1]

http://www.guess-works.com/Tech/ratio.htm

[DUF2 ‘65 Elf]

I have a 1965 Riley Elf with a 1275 engine and DAM 5626 gearbox from a 1989 Metro. The car is running 165/60r12 tyres
I have the original (maybe) central speedo with 1376 tpm.
I have no idea on the speedo gear. I suspect it may be DAM 2905 green 16 tooth
I need to change the speedo cable and may change the gear whilst in there (if this can be done with the engine in situ!)
Does anyone know which should the correct gear be to make the existing speedo as accurate as possible?

[mk1]

Please re-post to the technical section, here.

https://mk1-forum.net/viewforum.php?f=3