Do you have any estimate what rpm range the vibration is at? My experience is that it will be most noticeable above idle and below 3000 rpm.
Has it been determined that engine is running on all 8 and in a good state of tune? I have worked with engines that have the balance wrong and often times it is mistaken for an engine miss. I suppose the opposite could be true.
This is very true. I will further diagnose this and post results here. The engine idles nicely and sounds good, but I agree that I need to check for mis-fires etc. I will do that tomorrow Sat 9/13.