I have successfully installed Catalina 10.15.6 on similar rigs, the only different is the mobo which is a cheap Chinese X79 (actually using H61 chipset).
The trickiest part is to get Power Management to work on that E5-2420 v2 CPU. My hackintosh always has all cpu cores stuck at 1200mhz. I cannot yet make it run at 2500Mhz all cores.
Any suggestion to fix that is appreciated.