Someone asked this question a while ago and I'm sure someone answered it but I can't find it. So I decided to go out and see for myself.

It turns out that a 2nd gen speedometer cable will fit in a 1st gen RX-7 (or in a S3, 84-85, at least). The 2nd gen cable is just a little bit longer than a first gen cable, but other than that it works just fine.

 

Very good to know since you can still buy a FC speedometer cable new, but the first gen ones have been discontinued.
Thanks for posting!

 

ohh sweet!! thats great info!!

 

i think they are around the same length as an FB auto trans speedo cable.

 

That makes sense, seeing that the auto tranny is longer. Maybe they discontinued the FB cable because the FC cable fits the S3.