[ElGracho]

Speaking of the larger trucks (bigger than 1 ton...) they too had many variations. Not all of those trucks had the small air gage or small vacuum gage as previously mentioned so some of them are directly interchangeable with the CK10-30 factory Z53 style packages. If you find one of these, beware that there are also different speedo head designs so you may not be able to use your old speedo head to maintain your current mileage and the plastic gage 'bucket' and printed circuit for the tach insturment cluster is different that those that didn't have one so if you find a cluster, get the whole thing. KIILEW had an excellent description and to add to that keep in mind the oil pressure gage design went from mechanical to electrical 78.

One last point, there were dealer accessory tachs available (using a signal from the alternator) for DIESEL trucks at least in the 80's that combined the fuel gage and tach into one instrument that fit to the right of the speedo.