When it comes to lift, suspension should be your first choice. Doing too much body or shackle lift has a lot of negative side effects (and in the case of BL, it can even be dangerous should you get into an accident). You can do a junkyard suspension lift by adding leafs, so it does not become so expensive.
How are the Thornbirds working out for you? I have never tried them, and have read mixed reviews about them...
As for the mods, there are many threads here on how to boost the engine. Sharpxmen, in fact, is in on that club, as he is supercharging his (check out his build thread; his fab skills are fantastic!). There are also some turbos around (robtheplumber comes to mind, but there was more than one) and a naturally aspirated engine build (yjmechanic), plus many mods to squeeze more power out of the 4 squirrels (FoMoCo eFan, ignition, cams, CAI, bored out TB, spacers, high flow filters, injectors, headers, high flow cats, cat backs, gearing, etc.).