Mallory Unilite Distributor w/Pro Master Coil

[72step]

I have the ignition system in the subject line which I've had for 12 years or so with very little miles as my truck is not a daily driver and I'm wondering if I should look at a HEI setup. I gave it a tune up with new plugs and wires and when I test drove it , and I noticed lack of power and intermitent bad misfiring. I finally found that the cap wasn't locked properly so I removed and reinstalled that cap and it ran better after, but I'm wondering if I would get better performance with a HEI setup? It would also clean up the need for a coil, and ballast. What's you all's input on this?