Over and above the ignition itself, I found out that there are vented and non vented caps too, at least for my style flat or crab caps. Mine is none vented but thats all they used back then I believe, again at least with my style but the distributor itself has a small screen vent.
With the trouble I have been having getting plug wires and they expense of the cap (~$40.00) electonic conversion kit (~$145.00) I am beginning to wish I had just changed out the whole distributor. Too late to cut my losses now.