Hey Bullit,
I'll give ya a couple (ok that's an understatement) other hints since now you are tracking on doing it right. My truck is a '94, didn't notice where ya live and I've already started pecking on this keyboard so I'm not going back to look and start over!
1. Did notice you have a '90, in a few years that's 20 years! Start soaking them mounting bolts in penetrating lubricant now, every couple days, flood them with the stuff. Might even want to pull back the carpet or mat and soak them from the top and bottom.
2. I'd also suggest getting new cab mounts because I'm sure your old ones (if original) are screaming for replacement.
3. You may end up replacing all hardware. The BL kits come with bolts however Ford has some weird washers and fasteners under there. I used some fender washers not only to rebuild my body mount perches that were rusted but also to replace what was dust when it came apart. Also used grade 5 nuts. Yeah everyone going to say why not grade 8, use an engineers handbook and look up bolt tension and work load for grade 5, it will hold a body to the frame and slightly cheaper.
4. I had to use a 1/2 drive impact with 65 gal air compressor, a torch kit to heat bolts, and a sawzall to even cut out some of the body mount bolts! They had been in there 13 years and my truck was originally from Missouri! A lot of heat and cold and salt and sand, blah blah... stuff that fastens bolts, nuts and washers together like welding unless it eats it!
5. If you got arms that are less than adequate to facilitate postioning your ass in one spot, your feet against a pressure point, throwing your back out pulling on a breaker bar, and also holding the other end of whatever your trying to loosen (in the same awkward position as for the other side) that has been welded together from age and who knows what else! Have a competent friend or gorilla on standby with a basket of bananas or cold ones to assist you with said rusted heep!
6. Have alternate mode of transportation, cab fair, or a good pair of LPC (leather personnel carriers, ie shoes) to get yourself back to the hardware/parts store for replacement part of rusted, broken whatever that wanted to screw up your entire installation.
7. Allow yourself one more day than planned or maybe do bed and body on different weekends (even though it will look insane) to accomplish this metally and physically grueling project!
8. Keep your head and spirits up! It will be worth it, your truck will ride better, smoother and without the body shifting around going around the corner! And you'll love peering and drueling down into those little euro cars at those short skirts and less than grandmas table cloth blouses, as they pass you or vice versa or at every red light!!!! Yes there are other purposes for lifting than looking cool or putting on bigger tires to travese less than cooperative terrain! And all of you that already have your stuff up there, don't get all self righteous and say you ain't looking down too! Because everyone knows YOU ARE LYING!!!
Jay
Welcome Visitor! Please take a few seconds and 
I didn't end up having to mess with the ac lines or anything when i did my BL.
i can picture a ranger with boat rollers on for body mounts haha, should be an easy 10 inches of lift 
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