not charging

I have a 1975 Dodge Dart Sport that is not charging. I have a new alternator(powermaster) and new voltage regulator (Echlin) . The motor was completely rebuilt , we have power to alternator with switch on (blue wire) the green wire reads through when you turn switch on . no power but to ground . I had a spare new voltage regulator and tried it , though it is possible to have two bad ones I feel like I am missing something. Please explain to a simple man what I am doing wrong
Tell us about the alternator. I assume (dangerous) since you're talking about a "blue wire" that this is not a one wire alternator, correct? Also can you expound on what "no power but to ground" means?