yeah Im with chuck...
it would be extremely pricey/time consuming and you wouldnt end up with something as nice as a 2K silverado..
its all about the motor.. the rear end need not be changed, the trans is the same thing they've been using for years.
the motor (im assuming 5400 series?) is a next generation small block, designed to give max power and min. pollution.. its only 325 cubic inches and is not very impressive if you ask me.. sure it runs great, the trucks are downright fast, but its all upper rpm power, no good old fashioned tire frying torque.. for a fraction of the cost you could build a very very strong small block, and have an overdrive trans put in your '86 and outperform any 2K model truck, but it would have to be done right. NOT that "being done right" doesnt go for the 2K driveline swap, cuz its even more crucial that you do that one right.. just some food for thought, let us know what you decide to do..