Can you get away with running an electronic ignition (pertronix) while keeping the stock coil ?

 

I do.

 

Yes with Pertronix, or any electronic ignition that sends one pulse per cycle. There is extremely limited benefit to running a high output coil on an somewhat stock engine until you increase the cylinder pressure, or rpm well above 6,500rpms.
Well, that's not entirely true. If you are the type of person who runs 40 year old plug wires, cap-rotor, or have a 1" carbon dome on your stock worn out pistons, then yeah, a little more pressure (ie voltage) helps jump that nasty gap.
You'll see about 15KV-17KV out of a stock coil with a good reserve, which is sufficient for the average street engine, and up to about 0.40" gap limited to about 5,500 rpm redline.

Multiple spark discharge units can strain a stock coil due to the coil lacking adequate reserve. That is a good application for a high output coil, as is any kind of forced induction, or large gap (0.045" or more) applications. Also nitrous is a good application for a high output coil.

pertronix II has a better map for dwell and timing which will allow a higher primary voltage. This actually allows a stock coil to perform a little better. The down side is the coil runs a wee bit warmer, and benifits from being isolated away from heat.

HTH,