Bonneville.

The only limitations are safety regulations, engine displacement, fuel type and some classes have rules regarding body modifications mostly Production Class and the various Gas Coupes, which is just to keep people from multi-classing without changing the car.

There are no power restrictions, no vehicle restrictions, just classes for them to run in, there's even a couple unlimited classes which are mostly streamliners.

Land Speed racing is the final boss of grassroots motorsport, anyone can compete. There are records for mopeds out there I am not kidding, last year some Youtuber from I think New Zealand set a class record for a front wheel drive Solex supercharged moped using one of those Wish.com superchargers and he was the talk of the salt the whole week.

You can run any car you want with any engine you want and any aero modification you want, you just have to figure out what class it fits into so the record can be made official.