[sick472]

I did the dual tanks on my 85 K20 last year (or the year before) and I think it's best to pull the bed and then drop the tanks. There is a high chance you will kink the rubber lines when the tank goes back in. The first thing that gets you (without the bed removed) is that you wan to put longer rubber lines in to make it easy to attach them and when the tank goes up...there's just not much room for any extra line length. Having the bed off allows you to get to those lines with less difficulty AND inspect for kinks. You just cant see in there with the bed on. BTW, the cab would have to go UP way farther than it's worth to make that happen unless you are in the process of tearing the truck apart anyway. My 2 cents.