I have had so many discussions about this subject. I am an experienced racer and have had some thrust bearing issues. Don't go into techy talk and saying I am doing something wrong, I know very well how to set up a clutch(centax) however it comes down to trust for me. I know some of my fellow racers have never had an issue with a thrust bearing blow but I have and when it does kiss your racer over.
I have experimented with different alternative methods for ensuring and bullet proofing my drivetrain for a 1hr main, and I am sorry for all you thrust bearing fanatics but I have no faith or trust in the thrust bearing.
Curently I am using a high end bearing that was rubber sealed, I take the rubber seals out and pack it with Tamiya anti-wear grease. I then use a shim the size of the smaller metal bearing ring on 1 side of the bearing and a side from a thrust bearing with the grooves placed towards the regular bearing(I very carefully dremmeled down and made sure it was smooth! the inner part of the thrust bearing plate so that it did not touch the smaller bearing ring and made direct contact with the larger bearing ring(i made sure to properly lube everything)
This is my fix and since I have built I have never had any problems and felt 100% confident in my clucth for not just a 1hr main but entire race weekend or longer, I have done over 10 race weekends and when I take everything apart everything is just the way I first ran it.
Morgan