Yet to find it…if there even is one. Don’t think there is, I suspect. I’ve a late 80’s black max 150 2.0 v6 on a cvx16. Still prop testing and only been out a couple of times. But I know it will run way over 6000 rpm for sure with a 23” at 66 mph. No idea how much over. But it will scream right up there if I let it. Need a 25” for trials now. Bring the rpms down a little. No sign of a limiter.