Hi,
I just recently bought a '84 N/A 300zx with 180k and noticed that when I drove it at highway speeds for a few minutes and then came to a stop, there was a loud tapping sound, presumably the valves. which quickly died down after it idled for about a minute. I wondered if the engine isn't getting enough oil or what. Any help would be appreciated.

 

Yeah, sounds like oil deprivation.

 

did you check the oil level???