I am not sure if the mounting points on my 86 are the same on your 85. I had the same problem putting back the replacement dash I bought. If I recall, I did right going left principle which means I lined up the mounting studs on the holes at the glove box area, then center AC vent and last portion was the gauge cluster area where the holes are on top of the cluster housing. I had to exert some effort on the gauge cluster area as it had to be pushed towards the windshield a bit and it finally went through. Hope this helps.
