wanna sell that 400?
nvm found it
dude just plop an LS2 in there. the cost of parts to make the 5.3 like you discribed would be more than to just get a better motor. at least with the LS2 you've got the option down the line to stroke it to a 427 and the LS2s are pretty damn nice to start with. I'm sure others have said this already but I was to lazy to read