Okay, for us dummies who are struggling to understand this, tell me if this is correct. The timing retard on all these boxes doesn't really become significant until high rpms. 7,000, 7,500, etc. For a motor that only goes to 5500-6,000, it is not a significant problem.
Kind of the opposite in my experience. Most of the retard comes below 4000ish and less above that. I don't know why that is. It seems like it should be linear. I don't test very many engines above 7500 .