[joe231]

Originally Posted by 77gmcjoe

The tach cluster is not from an 85. The double warning lights at the bottom of the tach indicate it's a 77 to 79. If it has a mechanical oil gauge it is from a 77, if the oil gauge is electric it is from a 78 or 79. If the oil gauge is electric (and you already have gauges - not warning lights in your truck) it would plug and play in your 78. I notice it does have a newer style fuel gauge, but other than not matching visually it would work just fine.

The other non-tach cluster is from an 80 and up model truck. The newer style lettering (for lack of a better term) and 85 mph speedometer started in 1980.