Not being Nikon literate, I can't offer alternative suggestions so just a few general points.
F/8 is going to be a little slow and therefore bring some ISO bumping noise into the equation....at least on days where the light is testing you. You don't specify which mirror lens but whatever the choice it's going to be quite short and stubby....not ideal for motorsport panning shots. Strange comment Bob?...maybe it is, but think about it this way.
It you were going to shoot (as in a gun) the moving car, would you feel more comfortable with a pistol or a rifle. My money goes on a rifle...the posture used when panning accurately lends itsself to a two handed grip well spaced for stability and not two hands very close together. Any small angular movement of the left hand will give a much bigger move at subject distance than if the hands movement was transmitted further down the lens. This normally fits well with the advisory "shutter speed equal to or greater than the focal length" as longer fl lenses are usually physically longer. The mirror lens doesn't fit the equation here and so you need even more speed.
Summarised, you would suffer with a minimum f/8 and probably need a faster shutter speed to boot.
Bob