Wow! I've been wondering about that one for a while now. My 70 300 has one. It wasn't hooked up and there was a plastic vacuum tank on the inner fender. The tank hit the floor when I had it off and didn't bounce well... So I just used the metal tank instead. My car doesn't have a vacuum trunk lock, but I'll bet the car that fender came off did.The metal one on the inner fender is your vacuum trunk release
aha, yes my car have the vaccuum trunk lock.
mabey this metal can is just for that?