Keep the 5.3ls or swap for a 6.0?

Hey guys, been a while since I've been on here. A little background on the question:
Ever since my truck sh*t the bed, my parents have been on the hunt for a vehicle. I believe at this point I am going to end up with a 2006 1500 suburban. A little background on this particular vehicle, because it's a bit of a unicorn, and I have the factory build sheet to back all this up.
It has the 5.3 v8, paired with the 4l80e tranny, with the heavy duty tow package and a separate trans cooler. It's 4wd, with 4.10 gears, and locking front and rear diffs. Hydroboost brakes. It's basically a 2500 drivetrain, packed in a half ton body. As it sits now, it has 230k miles. The engine has had regular maintenance. However, the transmission has never been serviced, and that is starting to show.
So, the delimma:
Is there any worth to swapping the 5.3 for a fresher 6.0, or just freshen and beef up the 5.3? The transmission is not a concern at the moment, as it will probably get rebuilt. Structurally, the vehicle is sound, with only minimal rust starting on the quarters, per usual with the suburbans.

All thoughts appreciated

Upon review, I realize I have posted in the wrong topic, sorry Doug

I'd just keep the ol' small block personally, I think those 5.3's are fairly reliable units.

The 6.0 is a small block too. I believe it’s a bored 5.3, but may be stroked too. I think the LS has so much more potential than the old 350/400 small blocks we used to have. I do love a good vortec 350 though....


Until that 5.3 blows, keep it. Then put a 6.0 in it because everything will bolt right up, and you’re already that far into it you might as well

This goes for any engine generally. You look at oil pressure when engine is warm. If it has descent oil pressure then keep the 5.3. Descent pressure is no lower then 30 psi with 10w 40 oil in motor. You can always thicken the oil to raise pressure. I did that for over ten years with my Jeep engine. But 30 psi would be the lowest to go for just reliability. I been building motors for 20 years, mileage means nothing! Care of doing the general maintenance does. Burning oil, running hot, a slight tick on a lifter, busted exhaust bolts, and so on, all can be dealt with without changing motors and still be reliable. Racing the motor or doing burnouts is another story and is just asking for trouble.

Swapping out the motor is no weekend thing to do it right. Keep that in mind when you need to be somewhere and the motor is out of the truck. Switching to a 6.0, keep this in mind, you will only gain 20 or if that horsepower for the price of the engine plus whatever you break for the extra 30 plus inches more. As a general rule, when deciding how much bigger to go in engine size vs power is 1hp per cubic inch of the engine. Besides, you don't have to put a 6.0 in the truck. All LS motors are interchangeable, Even most of the parts. And the aftermarket is a whole other ballpark. Gaining the 20 hp another way is way easier with just keeping the original motor with less frustration and cheaper. A good cam with a lumpy idle in the 5.3 would be way better then a stock 6.0. Or swap out intakes with a Corvette intake for better flow.

I have a 5.3 and seems to have plenty of power and is in my Avalanche which is a modded Suburban. Mine is at 295 hp. I get 13 mpg in the city. Not to bad but not good either. That 6.0 that you want would get 11 mpg when running right. I know this because my brother-in-law has a 6.0 in his new 2500 Silverado (2017). You want the power, you will be paying for it at the pump every other day. Something to think about.