Another small block turbo early valiant

Prine said

Hope your running a Cold Spark plug like a NGK 5671-9....

I popped a headgasket and piston on my 360 real quick because I forgot to swap in Colder plugs before the first test drive.

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I can almost guarantee that didn’t happen because of the heat range of your plugs. Sure a colder plug provides a “little” bit of a margin of safety with regards to detonation but if you destroyed a piston and popped a head gasket, the tune was too aggressive or you didn’t have enough ring gap, or enough octane, or all of the above. At that point a colder plug is not likely to save the engine.