Electronic speed sensor

[Ptoneill]

I am looking at putting an electronic speed sensor on my 79 with the TH180 automatic transmission. I am not familiar with this process although I did see several different ways to accomplish this. One is an adaptor to the outpost using the port the speedo cable leaves the transmission, can I still use the cable for the speedo? The second is a magnet assembly that goes around the drive shaft.

The drve shaft one looks simple, however it is diameter specific...does anyone know the exact diameter of the 124's driveshaft?

Thanks

[SoFlaFiat]

I just measured the short shaft, between guibo and bearing, at 70mm (2.75")

[Ptoneill]

Thank you very much....my caliper got stepped on!

[ORFORD2004]

I have one electronic speedo and i use the port of the speedo gear and made an adapter to fit the electronic sensor for Ford. Actually i made 2...