Re: 1988 thunderbird.
The 1988 T-bird is a stretched Fox chassis, or, in other words it is the same as the Mustang, Fairmont, Lincoln Mark VII, and others. You might find some kits for the Mustang, at least I think you will, but you'll have to be careful that it will fit the chassis. The stretch wasn't much at all, if I remember correctly, but it could certainly have an effect. You might find it more entertaining to build the car into a sleeper since you can fit 460s into the T-bird with adapter kits and make a seriously fun car.
Ron