No need to pull the numbers off the Velvet- all of them can be spun in either direction. You just need to index the pump correctly. Yours spins LH because its bolted up to a LH engine. Mine spins RH because its bolted to a RH engine. What it cant do is change the direction of rotation... so the prop rotation (which I am keeping RH) needs to match the engine rotation... thus, the RH engine.
58mph out of a ski boat is serious. HP is only part of the picture though- a fast hull will make up for lack of hp. I know of a 17' wooden inboard produced in the early 60's with a stepped hull that would run in the mid 50's with a stock 210hp y-block.