[Raptor]

I don't know about the flywheel and clutch being balanced together as a unit separately from the crank, I would imagine it isn't a big deal. I will check for you in the morning. We always have the motors we build balanced with the pressure plate in place and marked for reference. You know, one thing I didn't mention the other day when you were here is that whoever did the work on the motor before may not have lined the gears up in the oil pump which would put the rear balance shaft out of phase as well. It still could pass the insertion test via the access hole in the block and be off enough to cause an out of balance condition. You wouldn't be able to tell if it was off a couple teeth(in the pump) while doing a timing belt. Not that I think that is the problem, just one more thing to consider. It still seems like a balance shaft issue to me. The clutch could be off balance as well, but it would have to be by a pretty fair amount for that kind of vibration. Not a common thing.