This works with any chassis, if you are swapping a SR20DET into your Corvair this box will be effective.
All Nissan EFI harnesses are for the most part, self contained. They usually only split into the chassis harness for power, switched power, a few different signals, and the warning lights. Nothing too difficult to understand and recreate.
This box incorporates all of the relays and fuses we deemed necesary and important. Over years of sorting other people's swaps, we have seen countless different ways to make the stock EFI function. You could twist a few wires together and jam them under the battery cable every time you wanted to drive your car and it would work but, it wouldn't be right!