Both Pertronix & Mallory (Unilite) make systems that replace points, and fit in your original distributor. You can also use replacement electronic distributors made by many companies. On top of that, you have a gadzillion coil choices, and can also add MSD, Crane HI-6, and other CD systems. Much to choose from, do a search here.
My choice I am currently using is a Unilite distributor, Crane Hi-6 system and matching coil, Jacobs 8.5mmm black wires, stock plugs with a larger gap. Never a plug problem, fast starts, reliable.
I use the Crane XR-i in my 289. No-one seems to talk about it on here, so I thought it might be a pile of poo, but now I have the car running, I can't fault it.
I think the easiest way to convert to electronic ignition is to install an ignitor module in your stock distributor. The install is straight forward and takes less than an hour. You could replace your stock coil, cap, rotor, wires and plugs at this point if you've not recently done a tune up.
I think pertronix also recommends that you not have a resistor inline, and the classic Fords have a resistor wire in the harness, so you may want to bypass the wire by running a new wire between the ignition switch and coil.... but I'd double check that. It's been a while since I did one.
Bypassing the resistor wire comes into play with ANY performance ignition upgrades.
A heavy red lead directly to the battery for power
a smaller wire that wires to the original points feed, which serves as an On/Off sw only
Trigger wire(s) from the distributor for kicking the coil
separate coil wires for activating the coil.
The HI-6 even has an LED to show when it is being triggered, and an easy to set rev-limiter.
Just using this as an example of how a CD system is wired in. I'm pretty sure the MSD is the same way.