1974 Chevy Corvette Cannot get my Corvette to turn over

Hello, I have a 1974 stingray thats been in storage for about 6 months. Its been started monthly, and this morning, wouldn't turn over. We put a charger on it, the battery is charged, all lights come on, when we turn the ignition switch, the lights dim, but no click, nothing. We decided to give it a jump, same results. I am leaning toward starter but its in a storage cave and I really have on shot of repairing it, or I have to tow it out. Is there anything I could be missing?

Thanks!
Aron