alternator gauge drops and reads low when driving

Ok I'll check these out. Electrical is not my high point on vehicles. I'm more mechanical and body work. Thank you for the info. And 14.9 I may have mis heard the guy that ran the tester on my car. Any possible ways of checking for bad points in wiring besides visually checking them. I do know that a wire can look good and still be bad. And yes the alternator is a round back. Appears to be off of an old 318.