Patcon

Looks really good

I believe the bar has some thick sealant stuff between it and the outer skin. I was trying to figure out where your bar could be without the door having been "reskined". Doooh 😉

Is it the same color as before or different ?

https://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/exhaust-tube-muffler/california I found this diagram hard to read. I couldn't tell what was directly clamped to the cat and what was mounted to the car. I searched for part #66 but it looks NLA

I dont recall ever seeing that shielding. Maybe somebody can post up a picture. You could possibly fabricate a replacement if you knew what the original looked like

So does the cat you bought have shielding on it? Are you looking for the shielding that was above the cat, between the cat and the tunnel ?

https://www.rockauto.com/en/catalog/nissan,1976,280z,2.8l+l6,1209226,exhaust+&+emission,catalytic+converter,5808

His comment about "if installed on the passenger side, I have been told, you can't see out of it..." is interesting

Not totally. I know it was mis-mixed but I dont know where the grit came from, chemical reaction or dirt...

I bought bullet mirrors years ago which haven't been used yet. The passenger side is a wide view mirror like most passenger mirrors are

So here is where I'm currently at Most of the sealer is off the big surfaces. Still a lot of detail work to do! I just don't think I can get my shop up to temp and keep it there for painting. My shop is concrete filled block walls and floor. Totally uninsulated. There is an incredible amount of thermal mass to try to heat up and hold at temperature when it's 40dF outside. So I think for now I will switch gears and try to work on some other aspects of the car since it's too cold for me to paint. Possibly brakes, differential, drive train or other systems that I can bag up and keep clean while painting. This isn't my preferred method but it would allow some progress while it's cold outside... When I do get back to paint, I have some new blocks to try and some Mirka PSA paper

Yes a spacer looks like a good idea

I used really heavy oils in motors that were noisy or had excessive bearing clearances. I'm unsure sure whether 20wXX oils are the right choice or not. I wouldn't run a 50 weight oil unless I had an engine issue that convinced me otherwise. You oil pressure sounds very normal. so I would run the 10w40 probably. It's more flowable when cold but still on the heavier side. Running a 20w oil when its really cold can cause other issues

Are your oil pressures good? Do you have any excessive engine noise?

I doubt the engineers reversed the reservoir locations for no reason. Not totally sure what it was, but it costs money to retool and redesign parts. It doesn't really happen for no reason

It's probably a brass radiator. Just drain it good and let it air dry. Then cap the open ports once it's dry

The seals on modern electrical connectors are much more robust and water tight

I would think it should function either way but should be corrected at some point. Probably not the source of you brake dragging though. My guess is the front circuit being moved closer to the pedal has something to do with a rear brake circuit failure, but just a guess

I use lots of brake clean. I buy ot by the case. I have found it can remove some paints but that's pretty rare. It can also hurt some plastics. Now dont confuse that with carb cleaner!! I have found carb cleaner to be super aggressive at damaging paints and plastic

No idea. I think the best bet would be to just mock it up and make some measurements

The service manuals should be in the technical section here on the site or possibly at Xenon

Is the Ebrake cable pulled at that wheel or is there slack right there adjacent to the hub?

@SteveJ

Simple green is pretty benign. if it takes the paint off Purple Power probably will too. Drop back to hot water and Dawn dish soap. You might be able to up it to dishwasher soap which is a little stronger...

Magnets are important! I have some fender pads but without magnets they won't stay in place. I have asked for someone to put magnets on them for Christmas for two years now but no luck...