1968 GTO w/ 400. Eng and tranny have 9K miles. Last week after getting on the highway and having a little fun with her I stopped at a gas station. Came back out and nothing! A buddy jumped the car with no issues. The battery is brand new and reads ok. The car did fine for a week at normal driving conditions. I replaced the alternator just in case. Then yesterday after taking her on the highway and getting on her a little the same thing happened, but this time she won't even jump start! No sound at all with the key turn, WTH! Starter? Wiring harness? Short? I am a newbie, so go easy on me.