Your running a 94 xp with a 657 running 54?? Is this stock or highly modded? I have seen many 657 xp's running about 48. My at the time stock 787 gtx was spanking them hard.
A good prop for a stock 94 is the solas xo series. The concorde is a great prop, but the "swirl" feature slows you up a tad, but gives better hook up than a x series. And same for the skat swirl (the name tells ya) best hook up, not as great top speed.
So is the ski stock? If your running 54 I'm guessing no. If not, whats done? Different prop is needed from a stock 657.