Any reason you are advancing the cam an additional 2 degrees over the 4 degrees of ground in advance? I ask, as your DCR is pushing the mid 8's and the added advance just increases it.
Got a plan to start lower on the initial ignition timing, and slower on the ignition mechanical advance, and then work it up in stages? From what I can see, you are bumping DCR MORE than 1 degree with the drop in chamber size unless your X-heads were milled down some to smaller chambers. If you had detonation issue before, and you jump up over a point in DCR, I would not expect the AL material alone to keep you out of detonation.
