Some hei's have the coil mounted on the dist cap others have a seperate coil. They are basically the same. I have pertronix in my truck and have had no problems with it,starts every time.
If you really want an HEI you might talk with Tom Langdon he sells a mini Hei unit that is a drop in, no modifications needed, remove your dist put his in. It has factory parts so if anything ever goes bad you can get parts just about anywhere.
The only drawback with the pertronix is that if it does break, most parts stores can't help you.
