You may have to run a power wire to the powermaster unless your 85 had a power master setup. I belive the late 85s had powermasters in them. No big deal, we converted a 84 to an 87 setup, we only switched the front harness to 87, both manifolds all accessories up front IC, electric fan, radiator etc. also drilled the front of the 84 block for the oil drain. The long block is an 84. We only had issue with the powermaster which we ran a line from the alternator with a 30 amp fuse and took care of it.