['63GENIII]

Just a question. 9 - 9.5 CR puts the engine in the 91 octane range right? I keep reading that the sharp edges of the Vortec heart shape chambers lend themselves to pre ignition or detonation above 30-32 deg. advance. Raising the CR may make it worse? My budget says stock cast iron but little voice says aluminum heads. There's a set of new Pro Comps on CL for 950 although I haven't heard a lot of good things about them. Theres also a set of new, assembled Race Rite ovals close by for 1800 (gulp) which deep down Im thinking might be the right way to go. Which brings me to another question. I have heard that just having aluminum heads brings better cooling and reduced detonation. Is this true and on average, how much could the CR be raised by using aluminum vs cast iron?