Joe,
I've got an old Nikon, use either DX600 or DX800 film, set the aperature at the highest setting, and the shutter speed on PHI and have had pretty good luck.
The color isn't quite as sharp as with slower film, but it stops the action better. I'm using a 70-210 mm telephoto for the longer shots and a 28-80mm for around the pits and garage area, and the 50mm for most of the stuff in and around the media center, normal snapshot type stuff.
Should add that my camera isn't an autofocus, it does have a motor drive to advance the film and led's in the viewfinder to tell you if you're too far off with your settings.
I found the camera, with a flash, the telephoto lens, a 50mm lens, and even a camera bag, in a friend's pawnshop for $200. The 28-80mm lens was another $75, brand new on sale at Ritz Camera. I'd never used a decent camera before and while I have ruined some film, I've got some pretty professional shots from the races here at NHIS.
I tried a digital HP 215 but between a funky flash system, the poor viewfinder, and the shutter delay, had to resort to something more workable.
This old Nikon N2000 seems to be perfect for what I wanted and need. And parts are available to repair it if that should become necessary.
Even my wife is comfortable with the thing after about five minutes it took to show her how to use the different knobs and settings.