We don’t have any adapters that are specific to a 68’ Firebird. With that said, we did find THIS LINK that shows how another person hooked up to the car’s tail using custom-made rear brackets. Most people choose not to mount to the tail like that, and instead will use a standard set of leaf spring adapters as shown HERE. I believe there’s a good chance you won’t need adapters for the front at all if the front of your car is similar to the mount as shown in THIS CAMARO PHOTO. With all of that said, just get yourself this 4pc ADAPTER KIT and you should be good to go since it comes with leaf spring brackets and some other goodies. Thanks for shopping with us!