On a shelf in the garage I had a cluster out of a '92 Police Caprice.
Rewired the connectors, added a ground and viola!
Installed and almost entirely functional. The tach is reading hilariously high. We think it might be expecting a 4 cylinder signal and it's getting pulses right off the coil. I need to get it someplace where I can get a steady state cruise in lock-up to see if it's a fixed ratio.
Note the mileage! That's accurate (and a pain to make so).
By the way, GM, the connectors are the same for the Chevy 9C1, Olds Custom Cruiser and Buick Roadmaster 91-93. The placement of the gauges is the same for all three. Why don't they share pin-outs?
I had to move 13 wires from one pin to another, plus add a ground to change from Oldsmobile to Chevrolet. The Olds and Buick share the same circuit board, but rearrange the lights so there's like 8 wires that are either relocated or omitted.