Van's has that engine for:
IO-360 180HP
Part Number = EA IO-360-M1B RT
Price = $33390.00
Which is way too much money. If you're going to stick with the 180 HP fixed pitch metal prop (the parallel valve M-2 horizontal induction, no bump in the bottom cowl) then you might check out Aero Sport Power.
http://www.aerosportpower.com/prices.htm#NewEngines
$24,500. Fixed pitch.
Maybe you could bump it to the IO-375 for a few more bucks..take a look.
I don't think you should do a 200 HP with a fixed pitch prop. All of those are angle valve engines which are larger and more $. Also, to take advantage of those ponies you would want a constant speed prop. More big $.
Just my opinion, your mileage may vary.