I have changed from points to a breakerless ignition in my 67 330 4bbl HC. Do I need to upgrade the coil? Thanks

 

Not unless you want to, follow the manufacturers wiring instructions for a stock coil.

 

You replaced a mechanical switch (points) with an electronic switch (transistor), so the ignition system won't operate any differently than it did before. You just replaced the mechanical switch that is prone to wear during use.

 

Two things to consider.

1) Coils do break down and require replacement. This is unrelated to points or electronic triggering. If your coil is decades old or at all questionable, it's cheap insurance.

2) Many electronic conversion kits either include or recommend a higher energy coil. Skeptics may think this is just an upsell for more profit, and they may be right, but the coil internal resistance may be better matched to the needs of the trigger circuit.

 

Exactly. The electronic circuit likely has a different dwell time than points. This could result in less coil output or an overheated coil. Follow the manufacturer's suggestion.

 

The OP does not have to change the coil unless it does not meet the primary resistance requirements as stated in the instructions. If the coil is good and not leaking there is no reason to change it un less he wants to. The engine will run as good as it did with points.
http://www.pertronix.com/docs/instru...heets/1181.pdf

 

The electronic ignition coils have about half the primary resistance.