I have always read that the Hemi combustion chamber is more detonation prone and needs more octane.
It's the exact opposite of what you have read. The Hemi has the most efficient combustion chamber shape of the era, and a centrally located spark plug. The flame front has an equal distance to travel in all directions from the spark plug.That reduces its octane requirement.
[img]http://i.imgur.com/boeexFms.jpg[/img] 31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
