Actually this card goes into IIsi PDS slot because IIsi do not have a NuBus slot. There is one another type of card that can be found on ebay very easily that converts the PDS slot to NuBus slot only w/o any pass thru.

As I said this card goes into PDS slot. The lower slot in the picture which is shorter than the upper slot is NuBus and the upper slot is PDS and it accepts Powercache or Turbo 040 but I am not sure about Turbo 601. I have one IIsi Turbo 601 adapter however it has only one slot no PDS pass thru. I ordered TwinSpark adapter as well.

Collecting all the parts will take some time. My ultimate goal is to use Turbo 601 in SE/30 with IIsi ROM. I will report my findings in my web page.

Don't hold your breaths though. }