I agree with Greg that the factory thrust washers are tougher than torrington's and IMO there isn't that much to gain by rollerizing a 904. If you were only drag racing it and looking for that last .010 in the 1/4 it might be something to consider
Almost all modern transmissions from the big 3 used Torrington bearings for many years now. The overdrive in all the Chrysler truck use torringtons to handle the pressure of that 800 pound spring.
They live in a diesel application, the thrust washers do not Imho
