Ignition boxes - worth it for the effieciencies

I think I have 5 msd 6al.....2 are in use...with one or two as spares...and as said above they go back for repair if needed.....

the one msd 7-2 has been rock solid for many years now...

and I have one msd 6C I bought back in 1979, it still works...must have parts that were made in the USA in that one.