I don't have a B52 23, so this may be less helpful. On my 16 F22 with 400 (so, a lighter boat with a bit less power) I ran a 2277 up at Lake Tahoe at 6200 feet. 2277 was great for wakeboarding and cruising (could hit WOT and 40 mph with 12 people in the boat). However, loaded for surfing (my prefered surfing setup amounts to about 4500 lbs, with about 600 of that in the bow) it struggled to reach and hold 11.6. No way it would have planed out with all that ballast...but I don't run that way anyway. Conversely, with a 2249 on, it would pull full ballast to surf speed without much issue. Ultimately, I ended up going for a 2279, which is same diameter and pitch as 2277 but with less cup. I haven't tried it on Tahoe but so far at lower elevations up to about 4,000 it has been great. My point is that a 2277 might be the upper limit on your larger boat at your elevation but a 2247 should be workable and will get you several more mph at any given RPM than will the 2775.