Captain Obvious

Maybe it's just me, but I suspect the first thing your machine shop is going to do is convert your drawing to English system. With that in mind, I'd just do it for them. I know any machinist ought to be able to do the conversion, but I'd just do it for them. Also, is the pinion shaft diameter smaller than 35mm? If so, you're good. But if the shaft is right at 35mm OD, then a 35mm ID spacer isn't going to fit over it. You'll need to open up the ID a couple thousandths just to get it to fit and not bind when you try to slide it on the shaft. As for material, I think 1045 in the annealed state would be a reasonable choice. It should certainly be harder than the 1008 stuff.

The only possible use for an amplifier like that in 72 would have been to kill the application of the throttle opener device as you came to a stop. But in order to do that, your throttle opener would have to be the defeat-able style design, and I don't think that even started until the flat top carbs. Does your throttle opener control valve even have a wire going to it?

Wow! That must have made quite the noise!

And what about @Zup? Anybody heard a peep. Hey FrogSquisher. You still read the forum??

My thoughts? I agree. Having not been through this exercise myself, I'm not sure of all the effects of changing the pinion position like that. Maybe you'll get lucky and end up exactly where you need to be. And if not, you'll have a better handle on the effect(s) of the change.

Speaking of such things... I'm looking for one of the newer design spray bars. Any of you guys who went to internally oiled cams have one laying around they don't need anymore? The later design that looks like this:

That would be my assumption as well. Little bit here makes a large change there. If your measurements are correct, I think you are going to bind with a 12 thousandth thicker shim in there. Did you ever use some thing shim material to try to figure out what thickness (total) you really need?

I've had two 77's over the years and both of them had the flat floor and a plastic interior panel over the taillights. Maybe they switched mid-year in 77, but it's definitely not strictly a 78 thing.

Here's a hoovered pic that might answer the question. I don't think you use the plastic panel at all if you have the sloped deck:

Well assuming the radio came from an earlier year Z, (which is what the wire colors seem to indicate), the white and white/black pair are the two wires that fed the original (one and only) speaker. The white is speaker (+) and the white/blk is speaker (-). There is no way to get "stereo" out of that radio. Ever. You could get sound to come out of more than one speaker maybe, but it will never be stereo. In order to get sound to come out of more than one speaker, you would just put them in parallel, but you do need to be careful about the loading. The radio was designed to drive one 8 Ohm speaker, and it sounds like you are trying to drive two 4 Ohm speakers in parallel. If that's the case, that combo works out to a 2 Ohm load and the amp probably isn't going to appreciate that much.

Yeah, I think the first order of business is to definitively figure out exactly what thickness you need to get correct lash. After that, you can figure out how to achieve that task. As for the question about grinding the new washer... I was going to suggest exactly that. Assuming the new washer is thicker than what you really need, then knocking the thickness of that one down to what you need would be my first choice. Only thing that would make that plan questionable would be if there were some sort of case hardening on the shim. You should be able to tell once it arrives. It's not yet even guaranteed that it will arrive though, is it?

Well if you don't have any other option, try cutting out some of that .003 softer material. At least to confirm the overall shim thickness you need. If you can confirm the total thickness, it shouldn't matter how you achieve that total. For example, take the total, cut it in half, and buy two new shims that come to that dimension. Or 75%-25%. Point is... Whatever you can find available. You don't need to be tied to the original shim thickness and a .003 augment.

I moved to your other thread since you started there. https://www.classiczcars.com/forums/topic/68722-stereo-tape-in-280z-clarion-radio-connector/

I'm moving over here from that other thread since this is where you started. So just to make sure I understand the issue of what's going on here... You have a 77 car and you're trying to install a Datsun radio from an earlier year, presumably from a 76. This pic you posted above shows the typical black connector the used in 1977: On that connector the wires are as follows: Blue is +12V power in. Hot when in ACC and ON. One of the blacks is connected to chassis ground. The other black is the speaker (-) connection. Black/Red wire is the speaker (+) connection. Green/White is panel illumination high side. Goes to the headlight switch. Red/Blue is panel illumination ground side. Goes to the rheostat. So that's the CAR side of things. Can you take a pic of the back of the Clarion that you are trying to install? You have some pics above, but they don't show all the wiring. The connector is tucked under the radio.

Well honestly, I find that description of "full hardened temper" to be marketing jargon at best, and completely nonsensical at worst. By that, I mean... For something to be "full hardened" it means "was made as hard as we could make it and did not temper at all after hardening". If you tempered it, it's not full hard anymore. That's the whole point of tempering. But even before that... The description of the listing says it's 1008 steel, which doesn't contain enough carbon to even BE hardenable in the first place. You need a certain amount of carbon in the mix before steel will even react to a hardening process, and 1008 is well below that threshold. So, when I see "full hardened" 1008 steel, it really makes no sense to me. I would expect 1008 to be dead soft malleable whether you TRIED to harden it or not. The plastic deformation threshold would be very low compared to something that is (honestly) heat treated hardened. For example, if you take a look at the shims from McMaster. They also offer low carbon steel shims. 1008-1010 steel. And the hardness rating is Rockwell B40. The higher carbon "spring steel" shims (1074-1095 steel) is significantly harder at Rockwell C44 or at least B85 I'm curious how hard the original spacer is.

I just took a quick look at McMaster and the thinnest hardened shim they have is 0,1mm (.0039) about 4 thousandths, which is too thiick. You could grind the thickness of your original spacer down to need a thicker auxiliary spacer. I don't know why she swallowed a fly.

Hmmm. I'd be reluctant to use that Amazon shim material in this application. I think I'd want a hardened washer in that application. How high do you torque the nut on the end of the pinion gear? I'm worried that you would ooze a low carbon shim at high torque. Is the original spacer shim hardened? Does a file cut it easy, or just skate off the surface? But you could certainly use that shim material as proof of concept. You could cut that thin stuff (.003) with scissors for the OD. Easy peasy. The ID you might be able to hack out with a razor knife. I'm thinking that the profile doesn't have to be perfect, just fit over the pinion even if the ID is a little rough. Cut the shim, put it together and check the backlash. That will at least confirm for sure what thickness shim you really need.

I believe the 240-280 radios were all mono. Can you take a pic of the connector on the back of the Clarion?

Sorry to be the bearer of bad news. The beatings will continue until morale improves.

Here's a pic of the underside that I hoovered. I don't know what year it is, but it might help with your analysis:

I don't have any really good pics showing the belt reels, but i do think I have enough mediocre pics hoovered over the years to hopefully get the idea across. Here's one with the seat belt mount in place: And here's one with the interior stripped and you can see the mounting holes: Hope that helps!

They moved the seat belt locations around a bunch over the years, presumably chasing safety requirements and comfort desires. By the time they got to 77, the seat belts were mounted to the tops of the rear strut towers. Another reason why 77's are better. But seriously, there aren't any belt guides. They just come around the sides of the seats. Not quite as neck choking as previous years, but not that different. Maybe a little lower than what's on yours?

I do have a rear strut brace, but I won't make any claims as to the functionality / necessity of the brace. I didn't put it in. Came to me with the car from my PO. Here's a pic of the brace that was taken before I did the Fiero seats:

I don't know how severe the bump was in 75, but on my 77, the left side was tight dealing with the seat bolster up against the trans tunnel and converter bump. Some people perform the catalytic converter "hump bash" (technical term). Which, as the name implies... You bash the hump down with a BFH from inside the car to make more room for the driver's seat. I put Fiero seats in my 77 and passenger side was a lot easier than the driver's side. I did not perform any hump bash operations because I told myself that I might want to put a pre-muffler resonator in that location some time in the future. That was ten years ago maybe? Haha!

I like it! Sounds like a good winter project! Hope the project goes well with no surprised.