However, keep in mind, bore size also counts a lot in this mix.  Detonation is worsened by big cylinders.

 

But the tech literature is clear.  To avoid detonation, reduce manifold pressure, reduce temperature, and run rich.  Doing two out of three is probably adequate.  What the temperature, manifold pressure, mixture, compression ratio map looks like, I am not sure.  Only data will tell the deed.

 

Your comments, corrections,  and suggestions are welcome.  Just keep in mind that like Brent Regan, I know nothing.  I only simulate competence.  Use your own judgment and experience.  Your mileage may vary.

Fred,

 

Hmmmmm.... My Honda VTX motorcycle, 110 ci (55 ci/cyl) comes close to my 320 (80 ci/cyl).  It uses a 9:1 compression ratio, 4" bore x 4.4" stroke, 3 valves, 3d mapped fuel injection (MAP, OAT, RPM, etc.) thru 12-hole electronic injectors, 2 plugs/cyl, EI, liquid cooled (uh, well that's quite different), etc.  This engine produces 95 HP and 115 ft/lb at the rear wheel thru a less than efficient a drive shaft at about 4500-5000 rpm. It requires 86 octane auto gas. 

 

No detonation, AND it moves my fat arse and lots of chrome (1000 lbs gross) with impressive haste.

 

Just another data point since I don't even simulate competence although I did stay at a Holiday Inn Express once (and only once).