a side note,,, if you say a "replacement head" has to carry a 10hp hit,,, what that is implying is that any head other than a factory 559 head will be hit,, maybe thats why they took it off,,, because really,, they would be adding 60lbs to every car in the class
559m,,,, 559m1,,, and now 110m2 heads are all replacements for the original 559
