Suggestions of Mods.

I have an 03 z71 extended cab. 5.3L, 4" lift with 33" tires, the 5.3L isn't where i want it to be in the power range. I don't want to change my gear ratio's but i want to add power, mainly for pulling a 3500lb. trailer. Running 65-75 on the interstate, it will stay in 3-4 gear, because of the load, and i personally don't like seeing it run 3k rpm all the time. i usually get off the interstate and go back roads. I am thinking about a good head swap with a cam. I will eventually do a 6.0 conversion with full forged internals with a supercharger/turbo. but right now i just need something to get me by. Anyone know where to get a head and cam set up? or should i just go get the heads ported and polished?

A stock geared 5.3 with tires that tall that also has to pull a load is the problem. Lower it and take the big tires off and live with stock performance or mod it a bunch (including gears) to make up for the lift and big tires.

what is the stock axle gear ratios?

Not enough for that tire. Look at the G-codes in the glove box and we can tell you what ratio you have. It's probably 3.73.

well should i just do a LQ4 with forged internals swap now?

and a turbo for 33" tires and no gear ratio change...

even with the 6.0 with forged internals with good flowing heads won't be able to produce enough power with out an power adder?

Not with 33's and stock gears. IMO.

that is a shocker, my father-in-law has a 02 2500hd with the 6.0L and he has no problem pulling the trailer, i know he doesn't has teh tires, or maybe not even the gearing, but i wouldn't think it would matter that much.

Hah...really? There's a pretty big difference in a stock 6.0/4L80 and a stock 5.3/4L60 and add the tires and probably worse gearing and you have apples and oranges.

Forged internals make ZERO power they just hold high revving or forced induction stuff together better. What are good flowing heads is debatable. There needs to be a cam, converter, and gears to go along with a good flowing set of heads. Heavy, tall tires need a lot more of all that....especially gearing, to make a large enough improvement to justify the $$$..