Help with Rallye harness replacing standard harness 70 dart

I'm replacing standard dash with rallye dash/frame and cluster/rallye harness. I'm noticing that wire colors and positions in the bulk head disconnect are not matching the standard wire harness. I thought I could just replace the old harness with rallye harness - plug and play? Also the two 10 pin steering cloumn white plugs on the rallye harness don't match the standard plug wire colors.. Would appreciate any thoughts on this.