J heads and Lunati cam question

We were having a discussion on this very thing here: http://www.forabodiesonly.com/mopar/showthread.php?t=54162

I'm using Crane single springs installed @ 1.590 and am presently experiencing valve float with the 60401 Lunati @ 5100 rpm. If i was to do it over, I would have used the duals. There is some debate as to whether what I'm experiencing is actually valve float or a secondary ignition problem such as rotor phasing.