I heard from lots of people that he likes to sell parts off cars to needy people and then just replace them with reconditioned parts. Hoods, doors, wheels, etc. have all be replaced by ones from wrecked cars that have been fixed and repainted. Not too many happy customers after that. I met John Hennessey once at the drag strip in Seguin, TX and he was a d*ck.
He was out there in his new twin turbo Viper GTS that was that crazy copper color. I approached and asked how much boost the engine was running on and he said, "There's no turbo's on this car. Those are just there for looks (pointing to the intercoolers)."
I said, "That's funny, but no seriously, I thought these engines were pretty high compression, how much boost are you running?"
"I told you, there aren't turbo's on this thing. Those are just for looks!" He said kinda putting his nose up and laughing with his buddies as he walked off.
Then the driver of the car came up and said, "Dude, he's a d*ck. Ask me anything you want to know about this car, I'm the one who drives it."
Turns out it was running 10 lbs of boost, but what a bunch of work to find out a simple answer to a simple question. No need for him to be a complete a$$hole about the hole thing.
Anyway, just my experience with the infamous John Hennessey.
