Will 5.3 to 6.0 (LQ4) make a big difference in towing?

[BG1988]

My 2003 Suburban with 5.3L has 225k and I just upgraded my boat. 3.73 rear axle. Boat is about 6500 lbs on trailer. Love my Suburban but at 6000 ft elevation I lose about 30% of my power. 5.3L struggles bad with the new boat, especially on hot days and loaded down. Looking at dropping in an LQ4 (salvage or reman) if it will make a significant difference. Not willing to go LQ9 as 85 octane is expensive enough. I know fuel economy will fall off a cliff as my folks have a Silverado 2500 with LQ4, but I'm mainly trying to avoid buying a new truck altogether. Anyone done an LQ4 swap for improved towing?
Also,I bought a 2013 Tahoe this year with the Gen IV 5.3L. After CAI, straight through exhaust, and Diablosport tune, it didn't tow any better than my old Suburban. 5.3 isn't the answer for me at this elevation.

8.1L

 

[S33k3r]

This might inspire you: Turbo 8.1 Build for 2001 Silverado

 

[Sam Harris]

This might inspire you: Turbo 8.1 Build for 2001 Silverado

I enjoy his videos and work. Looking forward to some final results re: the 4.8 vs. 8.1 comparison…

 

[fasteddy]

A built 6.0 will tow it easy. I have an LQ9 with shaved 317 heads and a torque focused cam. I get 350lbs of TQ at 1500rpms and 490lbs at 4900rpms (crank)
And I still get 19mpg on highway at 80mph.....not towing. towing is around 12-13.
A stock 5.3 in 2003 put out 315lbs of TQ Max around 5000rpms.
A new 6.2L pushes around 460lbs and that easily tows my trailer with race car and spares about 6500lbs.

The only engine that will beat a built 6.0 towing is an SC6.0 or duramax...... superchargers are expensive, get heat soaked in summer, they will suck more fuel, and they need a very beefy transmission.
I stayed N/A with my 6.0 as I need dependability, and less parts is more dependable.

Torque moves a car and pulls trailers, horsepower is computed.

 

[Mudsport96]

A built 6.0 will tow it easy. I have an LQ9 with shaved 317 heads and a torque focused cam. I get 350lbs of TQ at 1500rpms and 490lbs at 4900rpms (crank)

And that is the key. Im pretty convinced that GM crippled the 6.0 with the wrong cam from the factory.
Why on earth would you put a cam from a f body in a truck meant to pull and carry loads.

 

[fasteddy]

I've decided to put the 6.0 Tahoe to the test on towing......Trailer + car inside + spares + tools is about 6K lbs.
Towed it no problema....I was worried most about the tongue weight. As you can see it is squatted a bit but not much.
I have Z71 springs in the rear. But it handled great!
If this Tahoe had an 8 or 10 speed trans it would be perfect. Towed about 200 miles round trip. 10-11mpg. temps were fine.
19+ chevy 4P calipers worked awesome.