Never heard of a spring being sold separate.
Look around at past sales of 67-69 Barracuda hood latches. Shouldn't be too expensive. Are these the same as on other cars.
Welcome from Simi Valley. I'm part of the San Fernando Valley based Mopar club that puts on the Spring and Fall Flings.
www.cpwclub.com Not sure if you've been to one of our Show & Swaps at Woodley Park in Van Nuys, but its the best place to find Mopar parts in the western US.