I have a sort of ratty set of gauges in my '72. Will the newer set of gauges from a '74 (Speedo, Tach & fuel) plug into my '72 or are there some big differences that would require some rewiring or ??
Thanks

The later gauges will work in place of the earlier gauges. The main difference is the later tach has a single turn signal indicator and the older gauge had separate left/right indicators. One way to fix this is to use two diodes to 'OR' the left/right lamp circuits together to illuminate the single bulb. Someone else out there may have another solution that would work just as well.

Very late tachs (may be '75/'76 only, but I don't know when the switch was) have different connectors on the back.

The turn signal thing has been debated before. My '71 and my '73 had two bulbs, but they both flash with the turn signal switch in either direction. This matches the behavior of my '69 VW, which also has two bulbs. Some people say the separate bulbs work separately on their car.

If you have seperate indicaters, they are supposed to work independently. If they both blink at the same time, the diode wiring has probably been removed, or is bacwards (?) or possibly the diode itself went bad. I had one that was wired backwards (easy to do), and once I reversed the wire, it was fine.

I have had a '75 in the passed and can live with the single turn signal indicator. My old one blinks on the correct bulb but it appears that there is some bleed over of the light because there is a slight amount of light in the opposite arrow.

The new gauge cluster is from an unknown year. I just know it is '74 plus because the silver center is not there. I'll just have to pull my old one out and see if the connections are the same. Might be a time to do something different with the fuel gauge unit to get rid of the idot lights.

Thanks for the comments.

I tried putting a 76 tach in my 70 this weekend and it acted funny. FWhen I plugged in the wires, the tach showed a bit more than 1000 rpm with the ignition on but the engine off. The connectors on the back LOOK the same as the early one, they have the same markings, etc.

Am I doing sometihng wrong or are the tachs incompatible?

-Tony