Who can build the fastest wood derby car? We have a track lined up so let the engineering begin. Serious bragging rights are at stake. Cars must be no more than 2.25" wide, 7" long, and weigh no more than 5 ounces. Double elimination bracket races. Attention Porter family and friends; There will NOT be an unlimited class so no rocket engines, flames, explosives, countermeasures, etc, LOL.