I've only had one hands on experience priming a V8 Rover. My MGV8 engine was junked after 100k miles and what appeared to be little servicing. When I took it apart, the pressure relief valve was badly scored. The plate over the oil pump (the star drive version), was also badly grooved due to swarf in the system. Despite all that and lashings of brown toffee deposits inside the engine, and also two missing cam lobes, it ran rather well. MG later fitted a modified relief valve spring to lift the pressure slightly, after customer complaints, after being used to watching the oil pressure gauge on the 1800MGB.
I soerced a new crated engine from Land Rover (contacts matter). I had to change the oil filter arrangement because the MG used a remote filter housing. I knew that priming was problematical, but the oil cooler on the MG provided the solution. First i did the vaseline in the pump housing and it did nothing. So I established which pipe from the oil pump was the out pipe. I then put a funnel in the end of that pipe, added oil, and with the distrubutor out, used a drill on slow speed in reverse, which sucked the oil down into the pump. When all reconected, I ran the pump again, this time the right way with the drill and did that until I got a reading on the dashboard gauge. This took a while. And it needed quite a few revs from the drill.
Obviously the later set up, as on the Plus 8, is nothing like this.
