Don't forget that you need a different ign switch, one with a 'start' position. You'll have to run the wire from the "start" position to the solenoid on the starter. If your truck was originally 12 volts, you should be able to swap in a 12 volt solenoid starter from a '60-'62 truck with a 235, and not have to change the flywheel.
The 12 volt starters used 168 tooth ring gears, the 6 volt units used 139 tooth ring gears.

good luck

chip

Preaching the Hot Rod Gospel according to the 4-stroke apostles:

Suck, Squish, Fire and Fumes