If you don't want to be on the limiter all the time likely more. I have a 27 XOB that I had pitched up to a 28. With the 250 and 1.75 gears, with a conservative motor height, I am on the limiter in about .3/.4 miles at 86 and change solo with my 250. I just ordered a 30 XOB. Todd still believes I will find the limiter because I run fairly light. It should still be pretty quick to about 91/93 I believe. To find max speed, I feel I will need a 32 XOB
*Disclaimer
I prefer acceleration and bow lift and drivability. I purchase my XOB with .25" of flair removed (adds a ton of bow lift, removes stern lift) I only run 3 group 24 batteries. I still have great holeshot, however he warns that removing the flair may eventually adversely effect my holeshot. I do not seem to be giving up anything up top however it runs with the nose a little higher that it does with the full flair and it takes a lot less trim to make it happen. Mid range is night and day better and has driven me to order them the way I order them. I do have to run 2 solid and 3 large PVS plugs as otherwise they vent more
I trimming the flair adversely effecting holeshot on 2 seaters much more than my 2+2 as my holeshot acutally improves when I add a passenger up front..... I have enough bow lift the way I run them that I am considering moving one trolling battery forward as I believe I will lose 0 topend and potentially gain a fraction of a second on holeshot........who knows, I like to tinker, part of being an allisono owner I suppose.