HELP! No power...?

Yup. A test lamp and wiring diagram should make short work of this.

Check for power at the big stud on the starter relay. This is the last "takeoff point" before power goes through the fuse link and into / through the bulkhead connector. Check at the firewall side of the bulkhead connector.

Then get a clip lead and reach up and find the ammeter connections under the dash, and check there.

Post back

Diagrams from "MyMopar:"

http://www.mymopar.com/downloads/1968/68BarracudaA.jpg

http://www.mymopar.com/downloads/1968/68BarracudaB.jpg

A thread with some service manuals. The 66 might be close enough to give you some help

http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual,+download