A Few Question's On A Body Drop???

I have this 87 EXT cab Im wondering the best way to Drop the body 3" .. Im just trying to figure out the Fire Wall .. and the rear of the floor, I have the Door thing were the jack used to be And I herd there was a different way of doing it If I had That ????? I dont see how .. but Im shur 1 of you's out there do ... So Can Some 1 give me a few Pointers On this 1... Thanks Alot (RX2000)

this might help