You can swap the points style out for an HEI. Just take out the old and put in the new. The points style has two wires that power it, one 12 volt from the starter that is only hot when the starter is engaged [yellow on 68], and one about 9 volts that runs through the resistor wire from the firewall junction box[pink/black on 68]. The resistor wire is hot when the ignition is on. That provides 12 volts to start and a lower voltage when running. An HEI requires 12 volts at all times. Remove the wire from the starter and replace the resistor wire with a non-resistor wire. Or put a solenoid [relay]near the distributor using the resistor wire to switch it on and off, and a good 12 volt source to power the distributor through the solenoid. I power mine through a solenoid and have 14.8 volts at the HEI when running.
The HEI has a larger circumference than the points distributor and has less clearance at the firewall but mine fits no prob. Sorry I don't know the colour of the wires on 67/69.
You can try googling "Hot rodding the HEI distributor" I have it but don't know how to attach links.