can an early gauge cluster be used in a non porsche
 

I think the Porsche gauge cluster is one of the best looks in any car. So, I'd like to use an early Boxster cluster in a restomod 65 Mustang. Does anyone know if it must connect to the ECU or is it simply a matter of getting a wiring diagram to identify the connections? thanks -

https://986forum.com/forums/boxster-general-discussions/43017-carrera-gauge-swap.html

I learned quite a bit about the operation of the 986-gauge cluster when I swapped a 996 cluster into my car. You can read about it in the thread that I linked above.

I am not an electronic engineer, but based on my hands-on experience I think the cluster would need to be linked to an ECU and other electronic components to work. My reason for this opinion is that the display is controlled by the programming in an EPROM. It must receive information from various control modules in the car through the four connectors at the back. There is not a mechanical speedometer or tachometer cable like there would be in an earlier car.

Although I don't think there is a "plug and play" solution, you can probably make anything work if you spend enough money and time. For example, you might be able to graft the Boxster gauge faces onto the original Mustang cluster.

Good luck.