Don't waste your time on trying to convert your ofac loom to ofab. It's much easier to just take out the ofab loom from your donor car. Take the whole bracket off with the map sensor, edis, and co2 pot, then you should then see the engine plug that will separate behind that you also have the inlet plug for the injector loom mounted on the engine which will separate. Also remember to take the ofab ecu.

Hope it helps you if you haven't already sorted it