Something else to think about. As GX said, almost everything effects steer. The farther back the COG, the more steer you will need to keep the car stable. On a long track, too much steer could translate into unwanted friction. It may be desirable to have a less aggresive COG so less steer is needed for a stable car. Less steer should translate into less friction in the long flat section, but will also translate into less speed at the start. Somewhere there is the magic COG with the right amount of steer. I'm a relatively new racer in the NPWDRL, so I do not have the experience racing on a 63' track. I have not ever heard of one at all until now. For me, I have enough trouble setting up my car for a standard 42' track, so I am going with normal prep and a normal car configuration, regardless of the length of the track. There is just too many variables and I really have no way of testing any of them.