Replacement drive model #

[Ayman Altounji]

I have several 1850R 2x550p3 servers each with 2x(4.3gb 7.2k) drives (349513-B21) in raid 1 configurations attached to smart raid 221 controllers. I am interested in replacing some of the physical drives with new ibm/seagate/wd drives (larger sizes/faster speeds). When I look at the original drives, I know they are oem from ibm, seagate or wd, but the part numbers are Compaq?s and not the manufacturers. Does anyone have a list with the manufacturers (ibm/seagate/wd) model numbers for compatible drives that I can put in my universal hot swap drive trays.
Thanks in advance for any help,
Steve