Hey Chad super nice build,
Not shure you would have the same set up as this guy does (project Schism on Pro Touring .com) but I read on his post page 2 about measuring the radius of the belhousing to make shure the shaft is centered on the crank, or it may cause a vibration a eventuly bearing failure?? just a thought sense you are having a vibration of sorts, he is running an LS3 with a Whipple charger I think, Hope you get it figured out.