I've got an '89 2500 5.7L 4x4 that I'm going to be updating for use as a work truck. I've got a dually rear end sitting in the yard from a late '70's Chevy 3/4 ton. When I put the flat bed on the '89, I'd like to also swap in the dually axle for a bit more load capacity. Will this swap in fairly easily as long as I match up gear ratios front/back or am I better to find an existing dually?