Re: 83 4.5hp
To convert it back to a standard shaft you will have to remove the 5" extension to the exhaust housing, replace the drive shaft with a standard one, replace the shift rod with a standard one and cut 5" off the water tube.
(with that model shortening the shift rod by 5" would be an option)
The drive shaft is $235 so you may prefer TDs idea
You could make your own for a fraction of the prices in TD's link esp as you dont need it to handle a 40 hp engine.