If reliability is your goal, keep it factory stock. Carburators will run 40+ years with only periodic cleaning maybe once every 10 years. If you don't like adjusting or replacing the ignition points every 10 years or so, you can convert to pointless ignition like pertronix, but then you introduce sensitive electronics into the combo which will fail much sooner.
Honestly, bone stock carburated and old stock distributor is what you want if you ask for reliability. That stone age "junk" ran fine for 40-50 years. and still runs. Not one modern electronic controlled vehicle can get there, not even close.
