Upgrading from Alpha 1 drive to XR drive

Okay picked up a new to me boat a 99 Lavey Craft 26 Nuera , it has a Alpha 1 drive I would like to upgrade to a xr drive what is needed to make the swap? please educate me, drives are new to me I have been a jet boat guy.......I will be upgrading motor also but want to do the drive first
....It looks like its had a Bravo drive on it before because there is 2 holes on top that are filled with silicone

Upgrading from Alpha 1 drive to XR drive