To be honest, theoretically you could see some speed increase based upon the spin speed alone. However, I'm not super-familiar with the whole SCSI -> SATA converter thing. Best I know of, there's only SAS (Serial-Attached-SCSI) to SATA, but I could be wrong - make sure it's not SAS as SCSI because that would not work with this 10k RPM U320 SCSI hard drive.
Also, there's the point of the converter may introduce some latency in your data transfers that would negate some or all this speed increase.
Finally, if it was run on a server, it may be near it's end of life, or have other issues with it.
TBH, you likely would not see a /dramatic/ speed increase. At best, you'll see a speed of 10/7ths the speed you're seeing now. It may be an increase, but again, that converter could introduce latency.
Congrats on the nice find though.