On the Tee Dees and Medallions the cranks are also interchangeable but quite different. The Tee Dee has a large square hole at the intake end of the crank whereas the Medallion has a smaller round hole. The timing is also different. On the later TD RC versions, the crankshaft is lightened and strengthened similar to the Killer Bee crank. i.e. ground away and hole in conrod pin.