Thank you . First I’m gonna test all four gauges. Next install the insulator on the ammeter. Then I will test as per dayclona . I will report back .

Why worry about the insulator material? Just get them already made from that seller. It uses two of them! One inside and another one outside, not just the one visible outside.

And sure any contact of any of the ammeter studs or shunt inside or outside with the cluster housing with make a HUGE fail. ALL THE POWER to the car runs throught that wires and gauge, except the starter motor.

Do it yourself a favor and check that ammeter inside and outside, not just because the insulators but also for tight or loosen studs inside the ammeter. That a very missunderstood and hated gauge because just afew guys really understands its function and how it works. Is a hard to beat gauge but really abused along the years, however very usefull if you understand its readings.

And get a nice powerfull alt and couple of parallel wire paths out of the bulkhead will help on get the charging system propperly balanced and protect all the charging system. Later will post a few threads about that.

UPDATE / what happened report. I now understand what happened. I installed the new/correct harness from the voltage limiter to the oil,gas and temp gauges. While i was connecting everything the insulator on the back of the amp gauge fell off. I connected the red . When i went to connect the black ..... hot hot hot. I disconnected everything . I found the damaged insulator on the floor mat. I am now a member of now you know club. After a break i went back and tested the gauges. Gas and temp dead . Oil and alt still work. The posts on the alt gauge were very loose and one broke off on the inside during removal. So all my wiring is fine. Voltage limiter is grounded and working. With 3 dead gauges i feel my best move is to order all 4 new . I will get new oil pressure sensor. Getting the gas gauge to work gonna be another task. Thank you so much for all the help.

😡😡

thanks for posting the update as it may help someone down the road
As far as the broken insulator

Be careful with grounding also. After my full resto (that I did) my electronics were wacky too. Discovered I had a bad ground to the dash frame that I repainted before reinstallation. Scraped some paint off, reattached the ground, no more problems.

I think Ammeter could be fixed using a screw and nut ( not a thick one ) to replace the stud at the shunt. The ammeter will "pop out" the nuts thickness but I think the cluster bezel still have room for that, and maybe the shunt stud provision can be bent/shaped a bit to save that. Some indexing of the nut could be required for a correct fit into the housing provision for the amm, then some lead added for better conductivity between screw and shunt and also locking the nut. Shure the isolation gets the hole made for the squared shape of the stud on the base to keep in place the assembly but can be made to work centering the screws when reasembling. As far I recall the repro piece you probably buy will get bolt and nut anyway, not any more a pressed in stud like originals. That's at least what I recall have seen around on the web about the new repro ammeters thought

I'm wondering how the gas and tem gauges could get damaged if they were in working order.

Note: they could be also fixed if the wire inside got burnt at an accesible area to twist them and get them joint again.

another thanks for the update !
two ways these kind of replies help. one, so guys that haven't yet had to deal with "xxxx" problem get a heads up on what to expect, and two, so guys like me that "forget" are reminded about what we did in the same situation.