This reminds me of something I saw on t.v. a couple weeks ago. Carroll Shelby was being interviewed and he said that guys would rent the Hertz rent a car GT 350 Mustangs and swap out the Shelby 289 motor with a regular Ford unit and then turn the car back in. I had heard about guys renting the GT 350's for a day at the race track but I hadn't heard the engine swapping story before.
Karl
