That is a pretty broad subject.....
The ignition could be upgraded with either a Pertronix to keep the stock distributor or you can refit an HEI type distributor.
An alternator is mainly a modification of the generator bracket. You can keep it 6 volt or make it 12 volt.
A 6 volt starter will work with 12 volts, as long as you don't hold it on to long.
Fuel system, you can go with a multi carb set up and split exhaust, we even had ne fellow retrofit a throttle body setup on his 235 engine. You can get manifolds for 4 brl carbs too.
I guess my first question might be what year 235 engine are you using and in what?
John
