The new latest spec clutch kit from UFC for your MCD (all types), the bell accepts stock mcd style pinions with the square drive. (single speed only of course)
 
This setup has been winning races across the world in 1/5 scale competitions and is now available for the MCD platform, perfect for high HP motors in your MCD (32cc+). Get the jump on your friends and youll be able to run an extra pinion tooth without loosing acceleration over standard 54mm clutches.
 
The Bell is designed with a recess on the inside so that you fit a socket cap retaining bolt through the inside of the bell and lock the pinion in place with a nyloc nut to prevent it coming loose.