Well the 80 pin drive I bought is not compatible. But I think I may have another option. A friend has a bunch of old 68pin SCSI stuff, in it is a IDC 50pin male to 68pin male adapter, a four device 68pin internal SCSI cable with terminator, and a 4.5GB HDD.  He was using the adapter for a old 50 pin controller so he could attach 68pin drives. could I use the same adapter on the Quadra's internal SCSI connector and use the same way. I know I could just try it but I thought I would check here first and save me the time before cracking the case open.