High compression blues.

famous bob said

I missed it, do u have alum. heads ? 10.9 aint too high if u do. Did u call hughs engines/ they deal w/ problems like this about daily. PM sent.

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I have alum heads and run California 91 Octane. I’ve got 9.7:1.

I’m on the edge of pinging. On a 95 deg day going up a steep steady mountain I had slight pinging (sounded light). I backed timing a deg, plugs, carb adj, and all good.

Imho, that “one full point compression increase with aluminum heads all else equal” is a false general statement. Especially with more street friendly smaller cams.