Tuning For Detonation

Rob, have you considered....(wait for it) EGR? A simple slant six bolt on if you have the correct manifolds for the EGR valve and then a sense line to manifold vacuum. It doesn't do **** at idle or WOT (both close it) but it does dilute the charge at cruise and lowers the chamber temperature. Can be adapted to older manifolds. Some have an adjustable pintle to change onset.