If that's the case then I would still forgoe cleaning up and I'd be saving to find a used motor or rebuild this one.

I also wouldn't put a new cam and lifters in this motor. If you are having an oil pressure issue, that will only increase your risk of shipping out a new cam.

A motor can run a long long long time with a bit of lifter tick. Even low oil pressure on start up as long as you let it run a minute before putting it in gear it can last quite a while. I'd let this one run until I was ready to replace, and I wouldn't replace until this one started making worse noises than lifter tick (IE rod knock)

 

Yeah, we will see. I would like to keep this engine running for at least the next year or so. Given that it ran good before I took it apart, I don't think it will be too hard. This gunk was a complete surprise, as this was one of the better Rover V8 engines that I have had.

After this, it will be getting the L83/L86 Gen 5 swap that it deserves. The rest of the Disco is in great shape - not a spot of rust, great Montecarlo blue paint, nice interior.

 

What oil are you using? Rotella has a lot of detergents in it for diesels. I had a really gunky engine in a D2 before and after a few oil changes there was a significant difference inside the engine. I agree with the comments above. Clean out the valve covers and drop the oil pan and clean it thoroughly. You can then inspect the oil pickup screen for clogging. If that’s not clogged I would seriously consider removing the front cover and inspecting the oil pump gears. The oil light is concerning. Do you know if the gears where ever replaced?

 

My valve covers were not quite as nasty as your covers are, but I soaked the in Zep degreaser for a while and then took the plates off. Once I had the plates off I was doing a lot of scrubbing, rinse, repeat. It took a while, but they eventually got reasonably clean. I too had hoped that my tick would go away once cleaned but it did not. When I got the head off, the #4 sleeve had pushed up about 2-3mm above the block. I was able to push the sleeve back down via a steel plate, old head bolts and dry ice. The ticking came back however so. I've just learned to live with it.

 

Old mechanics trick is to use a quart of transmission fluid with the oil as it has a lot of detergent and cleans components very well without any risk flush products can have. Run it with the transmission fluid for about 500 miles, change and repeat. Couple of times will do wonders.