I just bought a 97 z-28 camaro, and the speedometer reads faster than the car acctually drives. i.e. when I drive 60 the speedometer reads 70. Is there any way to adjust this or do I need to replace the speedometer?

Your speedometer can be adjusted. You can either take it to a speedo/tach shop and have them do it or you can get/borrow from a friend or auto parts store, a flash programmer to dial in your current setup and it'll allow you to calibrate the speedo. I used the DiabloSport Predator programmer to adjust mine.