72 c10 speedometer cable question

[John1aus]

I have a 72 c10 which had a 250 l6 and I have now swapped it with a 350 and turbo 350 from a 77 c10. Does anyone know if the speedo cables are the same? Thanks.

[snipescastle2]

The cable drive in the transmission is the same, uses a "Square drive" cable that the cable end screws onto the speedo drive housing in the tail shaft of the transmission.you shouldn't have any problems, just make sure the drive gear (on the output shaft is the same as the one on the old transmission and the speedo drive housing driven gear (the one that the cable is driven by) is the same or your speedometer may be off. For example: I have a 3:73 rear end gear set, in order for my speedo in my 700R4 to be correct, I needed a 41 tooth (black)driven gear and correct drive housing, and a grey 15 tooth drive gear (mounted on the output shaft) there are several speedometer calibration calculators out there, but hopefully you won't need it.
Ben