40 amp charging system to 16 amp system

[Kidd07TurboRXP]

Trying to help my dad out on fixing his charging system. Looking for info to swap to the 16 amp system. He has a 89-90 175 with the 40 amp system. I know the flywheel and stator mount will need to be changed out. I've tried to google part numbers but keep coming up with all kinds of them and not sure which one are correct. Any help is greatly appreciated or if someone has the parts needed we would be interested.

 

[Faztbullet]

Why are you going backwards?