I have an Adaptec aha-2940u2w SCSI adapter, and it has three internal connectors. High density 68 pin Ultra 2 Wide LVD, high density 68 pin Ultra Wide single ended, and low density 50 pin fast SCSI ...
Plug it in and see what happens. It's a fairly common card, so I wouldn't be surprised if XP has the drivers built-in. If not, you might be able to use the Win2K with it.