I was a Champion user but switched to NGK's about 4 or 5 years ago and am very happy with them, one is 340 w/ironheads and the other is 416 w/eddy heads
Gary
What number NGK's do you run and is it up or down from the normal heat range.
BKR6ES w/ eddy heads, , as for heat range I think it was a lateral move from the recommended RC12"s
Iron heads I'll have to check, can't remember right now
