Didn't know these were available or they had a problem breaking.My brother has a 904 converter that he used in the past that has a cracked hub.I was going to try it a some years ago but found the crack before I installed it.
Cracked hub on a 904 is very common. Years ago when I bought my turbo action pro series converter, Paul Forte asked e if I wanted the thicker hub on the converter. In order to use it, you have grind down
The raised area that is on the pump. The splined section that the input shaft is inside of. This makes room for the thicker walled
Converter hub. The thicker hub is much stronger. The other mod that helps with the same thing is the better pump gears I showed you because they eliminate one of the chamfers on the gears so that there is more surface area in contact with the hub. Also the lugs are stronger for obvious reasons.
