You could use an LS2 trottle body. I don't know what they cost, but they are significantly larger.
Other than that the things that made the largest difference on my truck are
1. Cam - I used a mild 212/218 551/551 115
2. Stall - I've just put this in, but everything feels snappier now.
No more trucks, but this is what I used to have. 2000 GMC Sierra, 6.0L-LQ4, Built 4L60, LS6 Cam, The Other Guys Headers, 3 inch exhaust and 7 chamber flowmaster, 43lb injectors, Nelson Tuning, Drop - 3/4 McGaughys Spindles, Bell Tech Shackles & Hangers. Best time 13.59 @ 106