One tough decision is will you run a 0.500 or 0.400 Pro Tree. Some hard core racers like the .400, but the .500 will make it more even to attract more cars to enter, not all the regular cars can go .400

ATCO's 10.00 index class uses the .500 Pro Tree.

Depends if you are trying to attract a lot of cars, or a special group of top ET style .400 cars.

10.90 SST runs a .500 Pro Tree
Super Gas and Super Comp run a .400 Pro Tree