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I know these engines like a lot of timing which I attribute to needing a lot of timing to allow the mixture time to burn efficiently. I don't know if you can do it with your combustion chamber/pistons or compression ratio, but at some point you can lean it out so far that the flame front doesn't reach the cylinder walls and it will run cooler. I'm seeing more and more pistons that have a raised center bowl to give it squish area around the periphery and give the flame kernal an area to propagate around the plug with a lot higher compression and less timing to burn completely. I can get at about 38 degrees for my beetle normally aspirated at 8-9:1 compression. I understand with the right cam and pistons and up around 13:1 compression they can run cooler and use somewhere around 20-22 degrees of timing to complete the burn. At 9:1 compression I have to back timing way back into the low twenties when I'm using a turbo with the old tech combustion chamber flat top pistons. My heads get warm quickly on boost but they cool quickly off boost too. I don't think I'd want to be running above 1400 F EGT too often unless you have real confidence in your valves and seats. I would even suggest 1200 would be much safer. Slants stock would make the manifolds glow at highway speeds, but I don't know what temp that is maybe 800 fahrenheit?
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