Had some more time to work on 2723.
2) Drained the old fuel (about 15-25 liters left) and changed the strainer. The old strainer was pretty good, but not perfect so I used the new one since they are not particularly expensive. You need a 21mm hex to do it. They are about $20 from bunnings.
2) the old hose from the tank to the pump was badly perished, so I replaced it. When I was looking at the job I did, for a minute I thought I was going to re-do it, as that was hose I realized I had bought to do a return line for the SLS on the 560SEC. However, looking up the spec its specified for fuel and oil so I am good.
3) I was going to use the supplied K-jet pump as it was what the car was installed with. However, the new one had totally different type fittings and the barb didn't fit. I ended up using a D-jet pump which was going to be less work to use than adapting the system to the original short pump.
4) The old pump had quite a nice valve, but I wasn't able to re-use it with the D-jet pump so I removed this. I also replaced a broken ring terminal on the car's wiring harness.
6) when putting a battery in temporarily, I noticed a ground strap that was connected to the firewall near the negative battery cable, but not anything on the engine. I couldn't see where it would go, but there was a single bolt where the heat shield would go on the exhaust manifold that was not fully tightened, and it looked about the length so I tried it there.
7) Plugging the battery in, the electrics came to life. However, there was a click but the starter did not engage.
8) I tried checking the neutral safety switch. However, the plug disintegrated as I tried to unplug it, so i'll have to see if I can get the individual pins back in for now. There is not much room.
9) My next course of action is to re-check that ground strap. I think it may go somewhere else.