I have been helping my neighbor with his 57 chevy pickup, he switched out the frame with a 81 trans am, now the battery will not charge, we pulled the postive cable off the battery while it was running and it shut off, ok bad alternator right, but the alter. is new returned it and got it tested, they say it's good. power is comming from alternator but it's not charging battery, needs to jump it every few days. he has to grounds to the frame. If anyone can help, because i'm out ideas thanks.

the only thing i can think of at the moment is check the battery wires, or the wire comeing from the alternator. ill ask my auto teacher, he might know.

Has he tried grounding it to the block instead?