Here we go again, WHAT SPARK PLUGS

swedefish said
I believe I´ve read on the NGK site that for every 70-100 you increase the power you should be 1 step colder on the plugs.
Also read that it´s safer to start with a too cold plug than a too hot..if you´re not sure what to use.
Anyone more experienced than I who can confirm or deny...?
I´m running NGK R5670-6 in my 383, 10.2:1, MP 284/484 cam.
Click to expand...

it's not necessarily the power level. it's the compression ratio. More compression=a colder plug. more compression doesn't always equal more power. and vice versa.