|The original hard drive may well have been jumpered CS (cable select).|
Did you connect the second drive to the same data cable as the original drive? Below are the specs for that workstation. Could have come with a SCSI hard drive too.
You could be running into an issue with 48 bit LBA compliance. That means the BIOS is not capable of configuring a hard drive larger than 137GB. Watch the POST screens at start up to verify all the drives are being configured by both the model number and the FULL capacity of the drive.