I wouldn't cry... I am running a 150XR on my 89 Starlite, 5.5" setback CMC Hydro-Jack, and can get 54 out of it with a no name 19p prop...but guess what? I am waiving at Mr 400 HP as he fills up his tank....twice ...while I am still having fun! I am adding another 8" with a bracket, so we'll see what that does... but no complaints at 54mph....but then again, I do plan to re-paint and repower next year with a 300xs...