I added a second cable clamp because all my wire exceeded the capacity of just one. The rubber grommet and the metal clamp can be purchased from SI:
Retainer Grommet Grommet
The top egess is the standard one that came with the truck and provides for the speedometer cable, oil pressure tube, and the temperature tube. The lower is of my concoction. It is a thick brass plate that mounts in the hole for the ignition coil power cable and provides for the vent trap drain tube, heater temperature control cable, and bull horn control cable.
These two holes were drilled for the PTO control cable (left) and vacuum operated Wolf Whistle control cable (right).