My experience with the 440 Source roller rockers dates back a couple of years. I removed the rockers and shafts after less than 1000 street miles for a cam change. Both shafts were already galled. I called 440 Source and the women I talked to wasn't interested in hearing my problem. I changed to Hughes stuff with no further problems. Any manufacturer can have problems with bad parts from time to time. I was more annoyed by the lack of customer service than the defective parts.