I've got a turbocharged blow through E85 car. The carb works great, plenty of fuel. My question is with timing vs. rpm and boost. Currently I run the car at 28deg of timing locked with about 14psi of boost. I leave at about 7psi off the brake and see full boost instantly. I have a MSD digital 6 box that has the single adjustable high speed retard. I would like to run my timing locked at 34deg to clean up the cruising and no boost situations. Is there any thing wrong with using an rpm switch to activate the high speed retard? Or is a pressure switch better. Does rpm increase chances of detonation, or would 5000rpm with 14psi and 34deg be just as dangerous as 7000rpm with 14psi and 34 deg?