Valve float should not have been a problem at the RPMs he was running at. As he said in his first post, his limiter is set at 7100. Valve float should not be an issue at that RPM.
IIRC, valve float becomes a problem for the duratec at an RPM well above where you should be venturing. Not even close to 7100. I would be surprised if a factory limiter came within 2-300rpm of where the engine begins to experience float.
