A TH 350 tranny came with my 350 SBO and my mech and I, swapped both into the car, but we can't find the hookup for the speedo cable.

Where is it?

 

on the tailshaft on the left side while looking at the tranny from the tailshaft end.

 

I don't know about TH350's but I know the TH400 on full sized cars had the speedo cable running to the left front tire rather than the transmission. I've had 1967 and 1968 98's with this and been told 1965 to 1970 88's and 98's had this setup. I don't know if there's a plug in the transmission or if the housing was actually a different casting than the ones with the speedo cable to the transmission. John

 

I found out it's a TH 400 tranny today which is good, but I'll need to figure something out