The Courtesy site says that factory rubber is still available.

http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/front-suspension

https://www.courtesyparts.com/oem-parts/nissan-insulator-rack-54444n3401

https://www.courtesyparts.com/oem-parts/nissan-insulator-rack-54445n3401

I used the energy suspension kit for my rack (late 260 / 280) and each bushing came in 2 pieces and fit perfectly.  In fact having them in 2 pieces made the install a lot easier.  Here's a link to the ones I purchased.  I thought ES was the only one that provided these in 2 pieces and so I'm surprised the ones you have from them are one piece versions. 

https://www.amazon.com/gp/product/B000MWAO66/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

A couple of other comments.  The Sentra wheel that you have does not look like the one I purchased.  The one I have is definitely deeper. I will try and get a picture this weekend so you can see. 

Also, I have the same billet hubs from TTT and at the time I purchased them they were listed as being applicable to all versions of the S30.  I should have known better.  However, when I went to install them on my late 260Z, I ran into the same offset problem.  I ended up working with the Arizona Z folks to exchange my brackets to the earlier 240 ones and they worked fine with the TTT hubs.  I informed Gabe about this when I ran into the problem and he acknowledged they needed to have a different setup for the late 260/ 280Z. I know they now list them separately but I assumed they machined a different hub rather than supplying the 240 version with a spacer.  Also, even though the spare wheel I purchased was deep enough to get over the Wilwoods (which look to be the same ones that @wheee! is using), the center hole was not large enough to get over the bigger center of the TTT billet hubs.  So I ended up purchasing a spacer from Z Car Depot (it's about 3/8" thick) that I can use between the wheel and the hub to make up the difference. 

Hope that helps.

Mike.

@Mike W that last post was garbled. Try again?

@Mike W

So not sure what you mean by "garbled".  I just pulled up the thread with my response and it looks fine to me.

Let me know and I'll post again if you can't read it.

Mike.

I used the energy suspension kit for my rack (late 260 / 280) and each bushing came in 2 pieces and fit perfectly.  In fact having them in 2 pieces made the install a lot easier.  Here's a link to the ones I purchased. 

LINK IS MISSING....

I thought ES was the only one that provided these in 2 pieces and so I'm surprised the ones you have from them are one piece versions. 

???? FIRST PART OF SENTENCE MISSING.

[mention=29917]wheee![/mention] is using), the center hole was not large enough to get over the bigger center of the TTT billet hubs.  So I ended up purchasing a spacer from Z Car Depot (it's about 3/8" thick) that I can use between the wheel and the hub to make up the difference. 
Hope that helps.
Mike.

Garbled or missing info highlighted in quote above.

Not sure if this helps, but the kit I used was all in plastic bags with the part number on the bag. They were the correct bushes in the Master set #7-18102. That was back in 2012 and things change, including the way they package their product. It could be a simple issue of wrong part in the kit.

Wow.  That is so weird.  The link and all of the other text shows up perfectly when I bring up the thread.  Not sure why others are having an issue.

Regardless, I'll try again to fill in the blanks.  First is the link to the bushings that I purchased and notice they are the same part number as called out on the sheet that @EuroDat posted - 7.10102.

https://www.amazon.com/gp/product/B000MWAO66/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

A couple of other comments.  The Sentra wheel that you have does not look like the one I purchased.  The one I have is definitely deeper. I will try and get a picture this weekend so you can see. 

Also, I have the same billet hubs from TTT and at the time I purchased them they were listed as being applicable to all versions of the S30.  I should have known better.  However, when I went to install them on my late 260Z, I ran into the same offset problem.  I ended up working with the Arizona Z folks to exchange my brackets to the earlier 240 ones and they worked fine with the TTT hubs.  I informed Gabe about this when I ran into the problem and he acknowledged they needed to have a different setup for the late 260/ 280Z. I know they now list them separately but I assumed they machined a different hub rather than supplying the 240 version with a spacer.  Also, even though the spare wheel I purchased was deep enough to get over the Wilwoods (which look to be the same ones that @wheee! is using), the center hole was not large enough to get over the bigger center of the TTT billet hubs.  So I ended up purchasing a spacer from Z Car Depot (it's about 3/8" thick) that I can use between the wheel and the hub to make up the difference. 

Hope that helps.

Let me know if this one is readable.

Mike.

Wow.  That is so weird.  The link and all of the other text shows up perfectly when I bring up the thread.  Not sure why others are having an issue.
Regardless, I'll try again to fill in the blanks.  First is the link to the bushings that I purchased and notice they are the same part number as called out on the sheet that [mention=25317]EuroDat[/mention] posted - 7.10102.
[mention=29917]wheee![/mention] is using), the center hole was not large enough to get over the bigger center of the TTT billet hubs.  So I ended up purchasing a spacer from Z Car Depot (it's about 3/8" thick) that I can use between the wheel and the hub to make up the difference. 
Hope that helps.
Let me know if this one is readable.
Mike.

The text before you @ me is still missing...!

Well for some reason the system doesn't seem to like how I am using the @ name convention so I will refrain from using that for now although everything shows up fine on my computer.

In any case I'll try again. Perhaps 3rd time is a charm.  Here you go. 

Regardless, I'll try again to fill in the blanks.  First is the link to the bushings that I purchased and notice they are the same part number as called out on the sheet that Eurodat posted - 7.10102.

https://www.amazon.com/gp/product/B000MWAO66/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

A couple of other comments.  The Sentra wheel that you have does not look like the one I purchased.  The one I have is definitely deeper. I will try and get a picture this weekend so you can see. 

Also, I have the same billet hubs from TTT and at the time I purchased them they were listed as being applicable to all versions of the S30.  I should have known better.  However, when I went to install them on my late 260Z, I ran into the same offset problem.  I ended up working with the Arizona Z folks to exchange my brackets to the earlier 240 ones and they worked fine with the TTT hubs.  I informed Gabe about this when I ran into the problem and he acknowledged they needed to have a different setup for the late 260/ 280Z. I know they now list them separately but I assumed they machined a different hub rather than supplying the 240 version with a spacer.  Also, even though the spare wheel I purchased was deep enough to get over the Wilwoods (which look to be the same ones that Wheee! is using), the center hole was not large enough to get over the bigger center of the TTT billet hubs.  So I ended up purchasing a spacer from Z Car Depot (it's about 3/8" thick) that I can use between the wheel and the hub to make up the difference. 

Hope that helps.

Let me know if this one is readable.

Mike.

This one worked! Thanks!

Weird. Mike's message looked fine to me all three times.

Must be the Canuck having trouble with the Texas accent.     I'm in the middle, so I understand both, eh?