79 to 80 cluster swap

[Sprinkler-Man]

I have a 1980 GMC K15 Grand Sierra step side that I am trying to update some damaged parts in the interior.  I have found a 1979 Chevy pickup that I can use as a donor for parts.  The instrument cluster has a tach in it where my gas gauge currently is.  I was told that I could switch out the whole cluster with mine and that my truck is already wired for it.  Is this true?

[blazing816]

Well it depends, if your original wiring has not been "hacked up." Best way to tell is to see if you have a wire on your dist. in the tach position, that will give you a clue if the stock wire is still there. Or if you want plug in the cluster and see if it works.

However if your getting the 79 as a donor, it will not be hard to look on here at the factory wiring diagram and find the wire you need and run it or use the wiring out of the 79. I am pretty sure the is a page on how to do this already, I am sure someone will pipe in with the link, I can not find it right now.

[Captkaos]

It will swap out, but you have to have the whole cluster assembly.  And you will need to verify all of the plugs front your existing plug match the tach cluster.  You also need the tach wiring harness, or will need to make one.

[Sprinkler-Man]

Thanks...I will thinkings on trying to plug it in and see if it works and go from there.  I won't get to it until spring because I have it put away for the winter.
What would the tach wire look like on the distributer?

[Captkaos]

just a wire.