There's nothing wrong with the HEI. If you don't cheap out with a module made of Chineseium, the HEI module is better than the Ford Duraspark since it can vary dwell and offer better performance. In fact, it's pretty easy to wire up an HEI module in place of any other module, Duraspark, MSD or whatever.
Some folks get very provincial when you start crossbreeding your parts, like using an HEI on a Ford. But you have to go with what works. There's nothing wrong with AFBs. They don't have the nearly infinite tunability that some Holleys do, but most folks screw those things up once you get past jet and power valve changes. In many ways, an AFB is easier to work on than a Holley since you can affect your tune up just in the rod and spring selection and never spill a drop of fuel.