It happened all of a sudden. My gauges quit working and I have no idea why. The only gauges that work are my mph and my amp. Its a 74' 260z. Any help would be greatly appreciated.

They all share a common ground, at least on a 240z. Your ammeter does not have a ground perse and your speedometer is mechanically operated. Your going to have to trace the ground wires to find out the problem (correct fix) or re-establish a new ground for all the gauges (easy fix).

I just joined this forum to share my experience with you. I had a very similar problem on my 1976 280Z (all original) two weeks ago. In addition to the symtoms that you listed the turn signals didn't work either. I consulted the Datsun workshop manual and it pointed towards the ignition relay, which is common to all five circuits. There is also one additonal common component, and that is the 10 Amp fuse for the fuel pump, which as I discovered upon troubleshooting yesterday was open. Not sure if this will help, but if you haven't checked the fuse yet, then I would start there. The fuse on my car is located in the fuse box located on the passenger side under the glove box.

I have EXACTLY the same problems with my 76 280Z I acquired a few weeks ago. No turn signals ( yes hazards), no gauges EXCEPT speedo and volt.

Final word? Check the ground, ignition relay, and the 10A fuse?

My money is on your 10 Amp fuse. It also is the easiest part to check. I noticed on your other posts that your Z has a swapped motor and the guages didn't work when you bought it, so it might be a harness issue. My Z is all original and has never had any electrical problems prior to this one. But in your case I would still start with the fuse.

I had the same problem it was a fuse it was on the bottem row like around the theird one from the right

I'd listen to cebu on this one since he has the same year car as the poster. Everyone else is referencing 280Zs and one mention of a 240.