70,
Ames sells NOS aluminum units #PN526AF, that's where I bought mine.
https://secure.amesperf.com:8443/qil...rt_num=PN526AF
-MSD-6AL PN8680
http://www.msdignition.com/ignition_6_6420.htm
-MSD Timing control PN8680
http://www.msdignition.com/tc_2.htm
I use the points to trigger my MSD. They will last forever firing such a light load. The MSD automatically adjusts dwell so long as you have the points set properly to begin with.
I've researched ignition systems and this is the best set up for a street car that never revs over 5500.
You might want to check into the Ignition boxes that let you map your own spark advance curve. That way you can do away with the springs and weights in the distributor.
My car idles like a champ with a RA-4 cam with 84 degrees overlap!