The following is from the Ramchargers 1980 catalog...
MSD-5C $49.95 MSD-6C $99.95 MSD-7C $169.95
All have Chrysler pentagon connector, and will take a 4 or 5 pin version. I actually got ahold of a MSD-6C off the internet last year still in the original box. I did make a shock base and installed it in my 70RR, works fine.