These comp cams come out of a 2006 Mustang GT and had been in there for 3000 miles. Have never had any problems. I am going turbo soon and getting turbo cams for the car so I won't need these. I hate to get rid of them considering how AWESOME they made this car sound.. They are NSR cams which mean no springs required, just install. I bought the cams for 699.00, I would like to sell them for 500.00 or 475.00. My name is Coly Graham and contact number is 2704079611 call/text. Live in Kentucky near Glasgow.