Offhand it sounds like the long lens and teleconverter will make for some slow shutter speeds, unless you use a very high ISO (or push processing). If you are panning shots with that long lens, then slow shutter speeds can actually give you some unusual shots. Where high ISO and short shutter speeds can be good is for in the pits shots.
Mostly I have done nightclub or nightlife shots at high ISO. Even then, a fast lens (faster than f2.8) can often mean very slow shutter speeds. Obviously longer lenses can be tougher to hold steady at slower shutter speeds, unless you can brace them, or use a tripod.
I use to use Kodak Ektachrome P1600, which you can have push processed out to ISO 6400 with reasonable results. Unfortunately it is now very expensive film, so unless you need ISO 6400, I would not recommend it. My most used nightlife film is Kodak Ektachrome E200, which I have used out to 4 2/3 stops push (actually closer to ISO 2000 to 2500 with compensation). This film blue shifts on extreme push, negating the need for a strong blue filter (an 82A works fine, about 1/3 stop loss). Kodak don't list anything beyond 3 stops push, so I advise some sort of test before you do this, though I can recommend some good settings. The other choice would be Kodak Portra 800, which can be push processed one or two stops. Check with your lab first to see if they actually do push process C-41, because when the can do that it will reduce apparant grain over simply processing normally and trying to compensate in the print. I have tried the newest Portra 800 at ISO 1600 (one stop push processing) and the results were quite nice, though with more apparent grain than pushed E200.
Filtration is another matter. I have found that often an 82A or 82B can function better than an 80A, and is much easier with an SLR to actually see through. Racetracks will have some unusual lighting, and it will probably give an interesting effect to let some of the track lighting produce some unusual colours. You could also use a blue gel over your flash when you do those types of shots, instead of having the filter on your lens.
Ciao!
Gordon Moat
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