I'm guessing that the factory tachs "supported" points vs elec ign?? Altho like Al said Brian has the upgraded electronic board. I dont know if the "upgraded" board was to account for changes in mopars electrical system, OR to make the tach itself more reliable(electrical vs electronic). Hope that makes sense.
Thanks for the link. I was considering sending my cluster to them to get it ready for it's new life. I always thought these tachs would operate with points or electronic. I know my test equipment does.......Hooks up the same way for both systems.