176

When I got my 176, it had no prop.  I was recommnended 422 (15.5 pitch) or 654 (same but 15 pitch)  I hoped to do a head to head comparison and had each on loan  Ends up the 422 had a vibration and I could not get a good run with it.  I kept the 654 and am very happy with it.  The 422, with the extra 1/2 inch pitch might get you a little more top end, but not much difference, I wouldnt think.  Might also negate the effects by reducing rpm a tad.  Dont know.  I get 44.+ top speed on mine with the "basic" 260 hp engine. If you are just slalom skiing 32-34, you dont need to squeak out every last mph, so the 654 might give you just a titch better hole shot.  

As far as rudders.  There are 3 that the boat might have.  The original was a small brass one.  I am guessing that is the extra one you have, and not the "top performing" 11A, the big rudder from Nautiques.  The second is the ugly stainless, which is on mine, and sounds like what is on yours. As you said, the little brass one performed badly, so CC went to the stainless one.  Purists recommend putting the bigger 11A on.  I have one to put on mine, but havent done it yet.  Also requires you to swap out the port, as the 11A has a larger diameter shaft, which in turn requires reaming out the fiberglass a bit.  I have been reluctant to take that on, but the word is, it makes quite a difference. I may this winter as I am spending more and more time in a course and improved tracking might be nice.  Otherwise, the stainless rudder is just fine.  I would not swap back to the small brass one.  

I investigated the whole rudder story a while ago, which I summarized in this thread on PN.  I still dont have all the answers, but I have reasonable photos and documentation to back the story.  (about 1/2 way down page 3)

The best evidence suggests the boat, once marketed and available, started with the small brass one, replaced by the stainless one because small brass one was a poor performer.   Although the "needed to detune the boat" story is all over the place, including from an employee at the factory at the time, I have not found that story backed up.  Unless....the prototype at the factory originally had an 11A and they "detuned" it with the small brass one before it ever went to market.  I have a feeling that is the actual story.  Once on the market, they went from the small brass to the stainless.

It sounds like you have the CC letter from the original owner.

A copy of that posted here would be a good addition to "the story of the 176 rudder"  

Here's Mike's rudder letter that came with his boat's paperwork