I used to be a carb guy, but now that Ive dragged myself into the 21st century, I'll never go back (Well, at least until North Korea detonates an EMP). Something you might check-besides the spark plugs-is your fuel pressure (a common problem). Could be the fuel pump (usually), the fuel filter, or the spring in the TBI unit. You should be running about 12lbs.
TBI can support upwards of 400 HP and its stupid easy to work with. Its basically a carb that has computer controlled jets and enrichment circuits. Im running Vortec heads and a 4 barrel manifold under mine and it runs great. Im also running EBL flash, so I can program my computer with a laptop, so that helps. But Im also in the process of building a LT1 for it, and I just bought the $400 4 barrel manifold for that-just to run TBI on. Well, that and a decent distributor. TBI can take you pretty much as far as you would want to go on the street with a DD, so, if I were you, I would keep the TBI and save your money for headers, cam, and electric fans (and of course the EBL).
If youre looking for torque, then you might want to look into running the TPI. It was designed for torque and wont hardly run past 5500RPM so its perfect for a truck. If you get the EBL (because you will need to tune it) be sure and tell them youre running TPI and they will install the correct drivers to run the extra 6 injectors. Oh, and get rid of the TBI heads and go with the Vortecs. The TPI base manifold is a bit expensive, but the over all package is well worth it.