What year is it? I know that the 2001's and 02's were based off the LS1 with 5.3L.. has 285 hp (crank), 232 bwhp.. and runs the 1/4 stock at very high 15's, almost 16's...

So are you leaving anything out? How does intake, exhaust, a power programmer, and a converter with shift kit net you 3 seconds off 1/4 mile times? I could see a second.. maybe mid to high 14's.. but I just don't see a 5000lb truck running low 13's on basic mods..

I'm not trying to dog on ya, just curious, that's all.