run stock 1000cc 750, or 600 engines in them. When you don't mess with them they are some of the most reliable engines out there. Those old engines might do good on the fairground tracks, but on the bigger tracks they really don't have the endurance or power. In the Mini Sprint feature I think only 4-5 cars dropped out, none were for blown motors. So maybe an engine rule would help keep these things have more cars finishing at the end? Just a suggestion, not trying to start problems.