Thanks. Out of the drives I picked up, only one of them was working properly and fortnightly it wasn't a model that would get full functionality. However, I had a drive in my Win 98 machine that would work, so I swapped those two. I made the necessary modifications to the drive, and it works great! I will have to check later if it is indeed fully compatible. I have herd some applications have issues with some of these modified drives.
The source for the mod on this drive is here http://jope.fi/drives/sfd321b/
A Samsung 321 drive was one of the drives I converted as well. Unfortunately it worked fine for reading the disk but gave errors when writing. Not sure if it was just a problem with that particular drive or if I did something wrong.