That seems about right to me. I have a 32' Wellcraft coastal. I was running twin 340HP 454's with 1.91:1 trannys with 22x20 3 blade props. Just put in 2 new 385HP 454's and went with 2.5:1 trannys and 22x25 4 blade props. Both setups ran out fine but I do prefer the new setup better.