I used a pertronix billet " plug and play" on my 440... I had to grind some material off of my 915 heads to make it work, vacuum advance is NOT adjustable, and all the mopar guys make fun of my cap..

It works well, very clean with black cap and stock looking wires, top of shaft has a bearing instead of stock mopar bushing. No wires to a "box" that my car never had ( 67 Bbody) running 12 volts to the Pertronix FT II coil.... Simply hooked it up to each side of the coil and run it.