Good Afternoon!

I have a 1988 Supra Saltare, and I recently snapped the prop shaft after the strut. I have looked at a lot of website trying to find a new shaft at a good price. Does anybody know the proper dimensions or exactly where to find one?!?!?!?!?! I am lost!
I have the PCM 454. The coupler is good and the strut is good...just need a shaft. I talked to one company that thinks its correct but I want to be sure....

BoatDesigns.com
1" dam
48" length
standard propeller taper
1/4" key
3/4" standard thread
$295 plus S&H

Is this correct? If not please help me find somewhere trustworthy to purchase one!

Any help is appreciate!!!!!!!!!!!!!! Thank You!