Couple ?s

I have a set of them, I had an adjuster break, it started clattering real bad about 2 blocks from home, I drove it home, pulled the valve covers off, and put the stock ones back on. Upon further inspection, I had another one that was broken as well. I called the place I got them and they sent me out 3 adjusters and nuts free of charge. I think they said a new set of adjusters was about $10-15 or something like that. They are sitting on the shelf now. I threw them on CL for $100 but did not get any takers so, they are sitting for now. I was reading that it may have been that I had too short of pushrods and the adjusters were too far out... but, I don't know about that... sounds like a bad design if they will break....