I first thought they might be from the L20B equipped 910 Bluebirds, but they have a perfectly fine mechanical low pressure pump off the block.
So it's most likely from the early CA20 Bluebirds as the CA series don't have a mechanical pump attachment. Not the EFI ones, as they will only have an EFI pump, which is intank.

The external pump sounds ok. But the Walbro pumps off Ebay shipped from the USA are the cheapest at ~$170-$190. My brother used a 255L/hour intank version on an SR20DET and has no fuel problems at 190kW@rear wheels. The Walbros are smaller and quiet, but they keep the fuel pressure steady when it's required.

To give you an idea though, my old man is running a 2nd hand Mitsubishi Magna intank fuel pump, from the early 1990s V6 magnas, and he's got a reliable 160kW at the wheels in his SR20DET. Those pumps look wimpy, but do the job.


Basically with EFI pumps, size doesn't always matter.