yurs78

Every answer is a great choice, there are thousands of different options that will all come close to what you want. I came on here asking the same things, and two years later I've still done nothing becasue to get the power I want doesn't justify the cost. (but I'm cheap) (I own a 03 1500HD CCSB with the 6.0/4L80E)
To get to the power you want at the rpm you want it in is a little tough in a 6.0. All of the dyno sheets I've seen with heads/cam the torque doesn't come in strong until 3000 rpm, then if you bump the compression to help in the lower rpms you have to run 91 or better gas. I think it's possible but you have to look at how much time you'll have invested and justify it. You mentioned 400rwhp/tq devide by .8 for power train loss and you're at 500 at the flywheel. This is exactly the figure I've been trying to achieve for the last 2 years. The only thing that will come close in a 6.0 with out having a 3500 rpm stall(becasue your power band is so high) is FI. But then you need to be prepaired to spend over $6000 just for the kit and the necessary supporting mods. That's on top of the cost of the motor swap it's self.
My first choice if I were you is drop in a vortec 454 freshen that pig up with a healthy cam, hell you could find some worked heads too (look into marine stuff for boats) That will have more power where you want it than any 6.0 could ever have. My brother has a '97 2500 with that stock motor in it. It has power for days, my 6.0 can keep up with it but it really has to work. If you were to put your foot into it he'd walk right away from me, and that's stock.
If you want power off idle to 5000 rpm the cheapest, easiest way for you to go is with the big block. You can do it with a small block but you just have to spend more. If you already had the truck ( a '99 or newer with the 6.0/4L80E) I would strongly recomend a maggie or a Kenne Bell for off idle power.
good luck and Welcome!

BLACK04VHO

iTrader: (2)

He is correct, the lsx engines donn start producing hardly any power until above 2500-3000 rpm. I use to have a truck just like your. What gears are you running? Is gas mileage a big deal? To get the torque that low you really need a decent big block. 454 is a real easy swap into your truck and can be had for almost nothing. have it rebuilt if you buy a used one. If you did go with a 6.0, I wouldn't get a cam that big. Your moving the tq curve up even more in the rpm range. I would stay with something 212/216 on 112 lsa. but a stock 6.0 with a radix is always good, I just sold my 07 classic 4x4 stock height(it was a serious sleeper) ran 13.2 at 104 in the 1/4, got 19 mpg on the highway doing 75-80 but i had 3.42 rear gears. as I stated before these engines just don't come on low enough until you get some serious cubic inches. I would actually say buy a 408 shortblock and work from their. you needed to decided how much money you also want to spend. getting the electronics, engine and tranny and some fab work plus someone who knows what their doing is going to cost some $$. up front it might sound cheaper but I don't think it will be over all.

Norcalz71

currently running 38s with 4.88s, eventually it will be 40s with 5.13s.

InchUp

iTrader: (2)

40's with 5.13's and an 80E transmission will do nicely on the highway. 2200 rpms at 70mph. Nice choice.