Let's see if I can answer all the questions lol
My head block combo is stock early 280ZX, N47 head and N42 block with dished pistons.
I got my valve cover from a guy on zcar.com, it's the JDM version, and I painted it purple.
I've already got an upgraded coil on my car (MSD Blaster 3) because the stock one was dying. I think a stronger ignition system would have given me more power than anything else, but I didn't have a chance to get an MSD before the dyno day...
The fan clutch, meh, if it ain't broke don't fix it in my opinion, and my fan has always worked great at keeping my car cool, and I can't hear it when I rev the motor so it must be in pretty good condition.