Its not the rpm that is hard on the hubs or causes them to break, its horsepower or the force put on the clutch when an engine seizes up or locks up or some other failure happens, from my experience. Most of the dealers dont even take the time to respond is another thing i have noticed, but Shannon Halbert in Ky will respond and help you any way he can, he is also a Hilliard dealer. I cant remember the name of Shannons buisness but i think its GoFastHP. For the price difference, the machined drum is worth the extra bit you pay because they are more true, which provides a better and more consistent lockup. Be sure to clean the shoes and drum with WD-40 before using the clutch, they come with some sort of preservative on them that you cant see. Get you an extra set of black springs and use 4 black springs in the clutch if you are using it on a clone engine. They are good clutches for box stock class and JR classes, much better than the MaxTorque or other clutches in that price range. They will last a long time with proper maintenance. I would reccoemnd getting the Fury or Flame with the Bully conversion drum rather than the Extreme Duty though, you can buy the E.D clutch at any tractor supply store for around $30 if i remember right, that may save you some money on shipping if you choose to go with the extreme duty. The bully conversion drum will allow you to use Bully style drivers, which just about every parts trailer at the track stocks and sells.....not many stock the hilliard drivers for the clutches.
