John, I guess that's what I am wondering. If a big 550 hp stroker engine is strapped to a dyno and ran up to 5500rpm, what type of vibration will come out of the thing? What's normal? I am talking about what you feel with your hand. I know that's not a very technical way of testing. All I can say is a very fine light vibration (a little rougher than an electric razor)starts around 5000 rpm and becomes somewhat more noticable from 5000 to 6000. I'm sure a stock stroke 340 balanced with light weight pistons will not have the same dynamics as a stroked hemi ...again what's normal... for a stroked hemi?