I assume this is the Dell T7600? It can do SAS/SATA. The motherboard has two SATA ports and two Mini SAS connectors. The onboard SAS are SATA only I think and the speed is like 3Gbps since it uses the Intel chipset.
You would need a RAID/HBA card and proper cables to use SAS of course. The 3.5" bays should be wired already. There is a cable that does power and sas:
https://www.amazon.com/d/Raid-Controllers/Dell-8-Port-Internal-Controller-Precision/B00ZDC999I. That cable seems to just have one hard drive hookup though. The H310 can also be flashed to IT mode (HBA) and generally came with the T7600. Of course that depends who/where you got it from. That is what I am using. The cable should be able to handle all 4 bays. I forget what the part number is.
To get 8 drives you need the 2.5 kit:
Installing Five or More Hard Drives Into Precision T7600, T7610 and T7910 Systems | Dell Canada. In theory you can order another one of those cables. The power supply should have enough power outputs. It is a pain to find but should be $60ish maybe.
I have 8 SAS Samsung SSDs in mine with the H310 flashed as an HBA. Havent had any issues with it.