I'm curious! (No, not in that way!!)
An 8 is going against convention, as it's a "hotter" plug. A cooler plug, and HRC recommends a 10 or 10.5, will remove heat from the combustion chamber quicker and more efficiently, which aids against pre-ignition and detonation.
I think both Wrench and Matt@TYGA have widely experimented with spark plugs in different motors/configurations, so will hopefully chip in soon.
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Andy.
NSR-WORLD.COM
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