Help... my 79 280zx engine is making weird noises both in and out of gears, increased loudness with throttle, the car feels down on power, and it's borderline undrivable. However it cranks quickly everytime and the engine does not misfire. If anyone knows what might be the cause please let me know. Or else I might have to tow it to a shop.
Here is the link to the video

It could need a valve adjustment, a part of the noise comes from the valve cover and the cover have not been taken off to be inspected in recent years. BUT I'm not sure if valve issue can be that loud. The noise in low speed comes and goes. Mainly is present when under throttle. BUT at times the noise might still remain when I shift it to neutral.
It's a 3 speed auto and it's barly holding up before this, although the car will drive forward and reserve, and the noise is independently from the gears. I'm hoping it's not the trany.

 

Cam chain, rocker arm(s). rod bearings, main bearings, really bad alternator/power steering pump/A/C compressor bearing........................Pull the valve cover, its EZ and check the rocker arms, you may have thrown a pad. You may be able to see if the timing chain is loose also. Pull all the belts off the front of the car and see if the noise goes away.