Remember, Money Talks!
go there with cold hard cash, shove it in his hand, and tell him I'll buy it. He'll let you go with it.
Now another question about credibility. You said
"I asked about the car itself It was a 1968 Nova SS 396/350hp."
That means you asked about what car it was, and he told you 68 Nova SS with the 396 right? So he knows exactly what he has in his hands. He would never crush it if he knew all of this.