I don't have a clue what you are talking about. The needs for plug heat range bear no relation from one engine to another. The temperature of combustion is relatively the same. What changes plug heat range is the ability for the head to absorb heat from the plug and the way the plug is mounted into the combustion chamber

Plugs have no effect on an engine overheating, actually the reverse is more likely.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician