FWIW I was on three 41' race setups all three were within 5 mph of each other when I was on them and I passed 100 on a couple of them. All had similar power as well, but each one had different drives one had 3a's one had 5's and one had dry #6's.
I don't disagree at all with that. We were also told our boat does 90MPH and we've seen 85. We didn't buy it because they said it went 90MPH, but geesh, say it goes 85.
I guess maybe in early May with no gas and a 2' chop we may see 90MPH, but we'd be grasping at everything to see it.
I have read that 3a's and 5's give good performance. As the boat was designed to run 3's back in the day it could have something to do with it. I have been told that huge motors + #6's means huge weight over the back of the boat, but in the #6 boat I was on I didn't notice any issues. Also, keep in mind today that 3a's and 5's are no longer made.... I am sure others with actually experience driving these boats will chime in, I was just a happy passanger