[7DMACH1]

I looked at your build sheet. The xe284h cam is part number 31-250-4. Comp Cams site says any cam with a 31 prefix uses the old firing order 1-5-4-2-6-3-7-8. If you are useing 1-3-7-2-6-5-4-8 this is your problem. I've seen it before.