Grab a decent used points distributor and stab this in it:
http://www.fuelairspark.com/fas/xr-i...licationshtml/
(It's the old Crane conversion. Yes, sadly now Crane is owned by COMP--but at least they're still in business)
I run this on my Chevelle, works mint. Just make sure to wire it up correctly--it's easy to zap it if you don't. Don't ask me how I know.
Anyhow--with this, you retain GM parts availability, and should the distributor itself ever crap the bed, just grab another one and swap the guts into it. Easy-peasey.