Here is what I have had happen in this area. 30507 LUNATI CAM has .585/.600 lift .230/.240 dur @ .050 Now I ran stock shafts broke, replaced with HD shafts broke as well. Ran end stands with stock shaft, was low on funds and thought why not try it. IT worked!!!! I was kinda amazed to say the least. I later bought the HD shaft but I did learn something. But anyways I think and this is my guess that the wiggle or fatigue is what gets the shaft to break. The support stand limits the wiggle and thus the stress/metal fatigue that breaks that end off. If your on a budget and had to pick between one or the other the stands are more important than the HD shafts.
