Full Gauge Cluster Upgrade

[93w/t1500]

A few months ago I tried upgrading the cluster in the '84 Suburban to a full gauge cluster from a 454 Suburban (an '88 I believe). The OE cluster in my truck is the base cluster with the idiot lights and the 454 cluster had all the gauges. I realize I'd have to change out the oil pressure sending unit but I figured it would be a direct swap. None of the gauges responded correctly and I pulled the printed circuit board off both clusters and compared them. They were completely different (wires leading to the batt light on the base cluster led to the temp gauge on the full cluster for example).

I'd like to upgrade the cluster because I plow with her but I don't know what year/engine is a direct interchange. Does anyone have a wiring diagram of the base cluster from an '84? What year did they change the cluster wiring or was the base cluster one harness and the full cluster a second harness. I did this upgrade on my '96 Beretta a few years ago and, other than the oil pressure sending unit, it was a direct swap.

Thanks