I like the LQ9 better, but that may be because thats what i have.

The LQ9 has 345 hp 380 torque, i dont remember what the LS1 has exactly but i know its close.

I think the 6.0 would be better just because you have that extra few inches.

The LS1 is lighter but i personally would rather have the bigger motor in the heavy truck. You wont be dissapointed with a cammed 6.0.