Here in Tulsa OK they run Midgets(the roundy round cars not...) in side our Expo center. The whole event is inside, track, pits, everything. I think they had something like 200 cars this year or at least close. There was 3 teams from Australia that came to run the "chili bowl".

This building could maybe support an 1/8 track indoors. Its a clear span building so no supports in the middle. You could run the track down the middle and pits on both sides and down on the lower level(where the track is for the chili bowl). IIRC they had 3 rows of pits this year. Just like your IHRA or NHRA event there was 24" enclosed trailers and 53 foot stackers with 5 cars in them...all inside.

The cost for a building like this would be huge but maybe an indoor event could be done once or twice a year. The floor is just like a concrete pad .
Best pic of the pits I could find.



This was the 24th year for the chili bowl. For the most part its a week long event with racing tuesday thru saturday.