good point, the assumtion I am making is the S damper is suited to engines similar to the S engine, ie reging upto around 7500 rpm, but that said the S crank differs substantialy from the std crank so god know what it is doing in terms of vibrations.... so hence my thinking of just stuff a viscous damper on and be done with it.
just for a bit of fun ive drawn up the overlap of all the large bore crank configs that sprang to mind.
Ive never heard of a 91mm stroke has anyone else