I replaced the temp/oil pressure gauge in my 77 280Z with a gauge from my 71 240Z. The connector from the 71 gauge was replaced with the one from the 77 280Z so it would plug into the wiring. I'm not so sure the gauge is working properly and wondered if this had anything to do with the difference in the gauges . The back of the 71 gauge has the same number of connection points as the 77 gauge. Has anyone tried this swap or would it be best to get a gauge from a salvage 77 280Z?

The 71 uses a different sending unit for the guage which is what's likely causing the problem.

Thanks for the reply on this. I just didn't think the gauge from the 71 was working correctly, but wanted another opinion. I'll get another one from a salvage car I have access to.

Or try a 71 sending unit.

I replaced the guage with one from a salvage yard 77 280Z and also replaced the oil/fuel guage while I was at it. All is working fine and since buying the 77 the oil pressure guage never gave what I thought the pressure should be, but I thought it was the sending unit on the engine. Now with the used guage the oil pressure is reading correctly. I got both guages for $ 20.00.