I got ahold of a local tuner and he said to go with the 5.3 because the ls1 isnt ment to pull, and the 5.3 has a much better torque curve. when i do pull a trailer its got my race car so with tires, fuel, and tools so im figuring roughly 6k lbs. what about a 5.3 and a cam? Im am now realizing after calling nelsons i do need a tune. Thanks again for all the help.