Id like to stay away from messing with the stock injection if I dont have to.
Well, the ramjet that I was talking about, as I recall is a standalone system. Hook up a high pressure fuel pump on the frame rail, using your stock tbi pump to feed it, hook up half a dozen wires to the new computer, and you are ready to rock.
http://www.carcraft.com/howto/56398/index.html
But if you wanna step out of the crate engine realm....I am about to step into a 6.0/4l85e swap into the gf's 89. Doesnt appear THAT hard, more complicated than the ramjet for sure, but I bought the whole truck (wrecked) from where I work for $500.....Granted not everyone can find that deal, but what I am getting at is it makes 300hp and it has the new style heads, block, etc that will easily make more power than the old style small blocks will and it will do it in a way that is easier to live with.
Lord knows I love my 496 and daily drove the hell out of it, but when I can take that 6.0 I am swapping into hers, stick on a centrifugal supercharger with a few other mods and blow my 496's doors off and still manage to idle smoothly in traffic without overheating......gotta say something for that.
If its something you can take your time on when you do it, seriously look into the newer LS motors, if its something that when you yank it on friday evening you have to have it going by sunday evening to drive to work monday, I would go with the ramjet.