New Build Trickflow 190 and quench

famous bob said

interesting, say a 11 to one , cast iron headed engine built exactly the same clearances and dimensions as an alum. headed engine , same everything except the heads mat`l .
Why will the alum.headed engine run good on 91 oct. , and the cast headed one wont w/o slowing the timing down , if at all w/o detonating ?

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My money goes to the more modern and probably more efficient combustion chamber design on the aluminum head gives you more margin before detonation happens. You are not going to convince me that aluminum handles/dissipates the near instantaneous thermal shock produced by the combustion cycle faster than CI and that makes the difference. If you had heads made of each material with identical features, you probably couldn't tell them apart without good instrumentation.