guys- help! my trunk lock isn't working. My brother in law was trying to unlock my '74's trunk and heard smething "fall from inside the lock" and now I can't unlock the trunk- the key spins, but won't engage. Any ideas? Thanks.

Try this.

Place one end of a 2X4 (about 18" long will do nicely) against the trunk lock and push it in. Then whack the other end with a hammer with a deliberate blow (not too hard or you will dent the rear panel) while someone else is exerting upward pressure on the trunk lid. Works every time.
HTH,
Bob