If you
really want a top-end car, you might consider more cam than what you have. The X-303 cam is decent, but it's probably not going to pull any farther than 6500, and
that would be with some pretty good springs and better than stock lifters. Also, the windsor jr heads leave something to be desired, especially in stock form...are they worked at all? Heads and cam are the key to a top-end car.
The spyder is easy to install and remove, so it would definitely be worth a try...but I would get a cam from Ed Curtis asap.
