Shaft Extension Kit 1999 90hp

I'm considering buying a C90TRX short shaft from a seller for $750. I really need a long shaft, but it seems like a good deal. Are extension kits available, and what do they generally cost (in U.S. dollars)? Also, the motor hasn't been used in a year. I'm thinking I need to at least make sure it turns over so I know it's not siezed up. Any other thoughts on things I should check? I wouldn't expect it to run, since the carbs probably need cleaning by now.

[boats.net]

Yamaha doesn't offer drive shaft extension kits. They are available through aftermarket companys for abot $500.00.