charging problem

Well I got my 318 running this morning without any leaks with the help of some guys on the forum. but I think something is wrong because when i turn on my headlights the amp gauge goes positive, also I brought my old alternator in this morning and got a new one and a regulator to go with it, but Its not charging. I can tell this because after the engine has been running for awhile I should be able to take off my negative battery wire and the engine should run off of the power from the alternator, but It doesnt, It dies. Can anyone help? Thank you, I really appreciate all the comments and tips I get. It will just make fixing it alot easier.
Author: 74dart