Now, some observations on the project. For newer trucks, this would likely go quicker and be more of a bolt-up. This truck was old enough that it still had the mechanical oil gauge, for instance. I had to re-plumb under the dizzy to mount the new sender, plus replace the water and tranny temp senders, and of course install and wire the electric speedo sender (never mind the transmission position gizmo.)
Also, it took a ton of custom wiring in the dash which is incredibly time consuming. Some of that is my desire to solder and heatshrink everything, and some is the fact that I have more gauges than stock.
Classic Dash (i.e. "Ion" here on CK5) supplies a number of wiring harnesses, which I'm thinking mostly apply to y'all with newfangled modern trucks. You could presumably plug right into the VSS for the DRAC-equipped trucks, and get the tach signal from the ECU, you could reuse the factory oil pressure sender wiring, etc. He also supplies a harness for each gauge, and a ton of extra connectors and wire bits and I don't know what all, so I certainly had more than enough stuff to do what I wanted to do. Even on the newer trucks, though, I would not expect that you could just attach harness A to harness B and drop it in, the way you do with a stereo. There's just to many variations of plugs on each end for it to be that simple.
And since my truck is so old, I had to run wires for all of it by hand. I had about half the wires already through the firewall since I'd added a tach and tranny temp gauge, but I still had to run a bunch of new ones, remove the mechanical speedo cable, etc, etc, etc. It's the little stuff that adds up the time.
Also, the dash panel fits a bit funny. A couple of the top mounting points actually go to the cluster, so I suppose I could have gutted it and kept it in there for those upper screws; as it was I just left them off. My truck is not entirely perfect

so the fitment, as it were, fits right in. Tankie's also of the era with the wiper controls on the dash, versus the newer column-mounted ones which would make the dash cleaner and fit tighter. If you were doing a show-quality truck, you might want to go the route others have taken and mount aftermarket gauges into the factory dash. You'd be in for a ton of work, but you'd have more control over fitment.
I don't mean this as a judgment on the product; I couldn't point at anything and say "Here's where you could improve it." The factory dash is just crappily designed and a miserable pain to work on, as we all know. JJ "Ion" was also very helpful, worked with me through the process and customization, and took care of me right away when Autometer missed some bits in the gauge they drop-shipped me. Nice guy, very quick to respond, definite CK5 good-guy vendor.
Overall I'm pleased and it's, duh, infinitely better than before. Yes, I *could* have taken the factory cluster apart and silver-painted it and cleaned all the corroded connections, but the gauges would still be four decades old and it would still be finicky. This is a bit more work (and of course $$), prolly about the same amount of time, and the net result is gauges that are VISIBLE in any conditions and won't blink going over bumps
-- A