Put me at 5000lbs and you are dust. My truck is 5700lbs+. AND you are driving a 6.0 vs a 5.7
That LS is not even in the same league as a quad cam, 32 valve HEMI. The engine is a overbuilt beast.
I mean, a pushrod 2 valve engine will have better mid range and low end, but in the end can not keep up.