I have a chance to purchase a rally gauge cluster complete with the console gauges. I am currently trying to find out if the donor what the rear axle ratio of the donor truck was so I won't have to deal with speedometer issues. My question is, did the first gen trucks use a unique wiring harness for the rally cluster or did they use a common harness with the wires just unused? If a unique harness was used what should I expect to have to do to correctly connect the gauges? My truck is a 1985 Ram 50 custom, 2.0L, automatic....bone stock...

Thanks!!