Watch out for Hennessy cars, If your going to buy one let him work the bugs out on the first 10 or so. John is not the best at tuning the car once he puts turbos or superchargers on them. Someone above had said it correctly just changing pullys or adding a supercharger to a car is only 25% of getting the car to perform correctly. I hope his money problems are also behind him. Hennessy is very creative and ahead of the curve with his thoughts on what makes a car go fast. But, sometimes he cant put it into the car.
There are a couple of Tuners here in Florida who are re-programing (chip change) and have changed the pully to a 2.7 and 2.8. I talked to one of them this last weekend at a large Ford event in Ocala. He is saying by just reprograming he is getting 635HP and 510 torque. Adding the Borla exhaust only gives you an added 8HP. But, per him, the sound is AWSOME. This tuner also told me the pullys are $500 each just for the part. Something about all the re-designes that were put into them by the manufactor to make them a quite as they are.
He told me he has set up a GT with the reprograms and a 2.8 pully on it. The owner has 3,000 miles on the car and is on his 3RD set of rear tires. Seems the 50 plus boost in Torque actually will let the back tires bust loose when you romp on it. I am not to fond of spending $800 every couple of months for tires.
I also talked to a dealer today about changing the pully and was told that it would probably void the warrenty on the engine. Ford would try to blame the pully change on any defects on the engine and it would be up to me to prove it was not the pully change that caused the engine problem. I have read somewhere that the engine and drive trane on the GT is worth in the area of $44,000. I dont think I need to run 10 flats (I wouldnt take my car to the track any way)by changing the pully.
Sorry I got long winded there. I will update the board when I find out more.