Never liked the results I got with Delta 3200. Could be just me.
Would go with a 400. Used to shoot Velodrome racing decades ago, though it was outdoor tracks. Very harsh lighting, very overhead harsh lighting, lots of raccoon eyes unless you use some kind of fill flash or bounce card to get light from below.
The lower contrast lenses you can use, and the lower contrast processing you can use, the better.
Good luck and have fun.