Speedometer cable length, from the Service Parts List:
For RHD, 5' 3", or 63 inches.
For LHD, 5' 6", or 66 inches.

The speedometer cable starts at lower right of gearbox tail housing, runs forward along side of the gearbox, goes up the right side of the bell housing. For a Left Hand Drive car, it attaches with a P-clip and hex nut to one of the bolts at lower bulkhead plate to tunnel joint one position shy of the center. Then it goes over the heater shelf, past the heater, and through the bulkhead to the speedometer. If the speedometer is in the far left position of a LHD car (not standard configuration), the cable runs under the master cylinder.

The longer LHD speedo cable is often supplied for RHD application (to reduce inventory).

Tachometer cable length, from the Service Parts List:
For RHD, 4' 0", or 48 inches.
For LHD, 35' 2", or 38 inches.

The Tachometer cable starts at LR corner of engine, driven from back end of the camshaft. Route it upward over the heater shelf, arounr the left end of the heater (if so equipped), through the bulkhead (with a rubber grommet), and to the tachometer. If the tachometer is in the right of the steering colum in LHD car (not standard configuration), then the passage holes through the bulkhead are switched for speedo and tach cables. For LHD car, the tach and speedo can swap locations using the same cables, by re-routing the cables.

For RHD the safety gauge and tach are always next to each other for sight with a single glance.
For LHD the tach was originally left of thespeedometer, and fuel gauge was left of the safety gauge.
For LHD it is common practice to swap positions of all four instruments to put the tach next to the safety gauge.