A body aftermarket gauge cluster...

Yes they are. His blazer has a tuned port injection 350 in it. The indicators are green arrows for turn signals, blue hi beam signal in the middle. Red is for parking brake/low brake pressure warning indicator. One amber is wired to his engine management computer as a fault light. The other amber light above the tach is a shift light. He bought a spectre brand adjustable shift light. We mounted the dial part under the dash, with the dial facing towards him, and gutted it on the light end so I could run the wires from it up into the cluster to that second amber as an in dash shift light.

Sonofabitch was a tight fit with the gages. 3&3/8" and 2&1/16" they just barely touch one another. A lot of measuring before I took the holesaws to it after bonding the aluminum to it. I modified the bottom of the surround hood because the bottom 2 gages didnt quite fit. You can see how its smoothed and radiused where they fit at the bottom. Stock is straight across. My suggestion to my friend when i started wiring it up was to put the water temp, oil press, and RPM clustered together on the right with the shift light, since that's the most vital information.

The cool part is we used the vehicles existing wiring harness for everything, except the added chassis ground wire, and 2 additional wires for the shift light. Thank God he had a wiring schematic for the truck. Then he just installed the gage senders for the water and oil, and plugged in his stock vehicle wiring.