A commonly used and well thought of alternative to the factory ignition module is the Pertronix unit. It is simple to install, relatively inexpensive, and very reliable if installed correctly. We have used it for the past 23 years.
There is also the Crane/Allison unit which uses a separate amplifier box requiring holes to be drilled for mounting and tends to cost more. We prefer the Pertronix.
As for the existing failed factory ignition module, leave it in place and clip the two wires as the vacuum retard unit is mounted thru it. Please search thru these forums for topics on ignition units.
Mildred Hargis