Unless engine is modified, changing heat range won't make any difference.
I had bad luck with NGK the one time I used one. Porcelain seal broke and dropped center electrode into combustion chamber....surprised you prefer Champion rather than NGK. I have always thought of NGK as realy good plugs. I never thought much of champion.
I had bad luck with NGK the one time I used one. Porcelain seal broke and dropped center electrode into combustion chamber.
Went through piston crown and sent a wrist pin needle bearing between exhaust port and piston. Nasty business. I never saw an engine self destruct like that. Plug had less than 2.5 hours on it and was the right color.
Did you write a letter?