Magnum motor with Mechanical fuel pump ?

Has anyone here actually used the Hughes extender? I had to get my hydraulic roller for my 273 ground on a Magnum blank because that was all that Bullet had at the time. I'm having a helluva time finding a woodruff key to fit the cam keyway and also work with the extender. I called Hughes today and talked to Dave, and he said they had never had the first complaint about the extender, so maybe I'm missing something. I saw a You Tube video where one failed, that I wondered if it belonged to @gdonovan ?