Is there a gear reducer for 25mm pump shaft exist?

Hello friends. I am wanting to build me a pressure washer using a Legacy pump. The pump has a 25mm shaft and I am trying to figure out what kind of reducer set up to use. Would love a gear box but if such gear box doesn’t exist then I’d love one of them high torque cog belts or if that non existent then gonna have ot settle for a v grove belts :slight_smile:
What are you pros would recommend?

Thank you!