The instrument cluster came with the truck. I took it apart and cleaned it up well, painted the needles, and polished the lens, and painted the ring around the cluster.
I'm not sure what pontiac the gauge came out of. I think it is a console gauge on something like a GTO. There are a bunch on ebay. I had to take it out of the housing and it fit really well in the left side. I had to dremel a little bit of the cluster but it was much or difficult.
I still want to put a tach in the other opening. I can't find one other than the ones for a V8. I might have to make some sort of circuit to make one of those work.