Thats a very good question, hope you get an answer for both our sakes.
Thinking about doing a 6.0l swap, but that will lead to a 4l80 swap too.

 

On the 5.3 my KB overboosted the engine very easily on the stock cam. The tune must be dead nuts. On the 6.0L, a cam made a world of difference especially with a longer exhaust duration. I have ran 12-15psi trouble free for 2 years. Your tune will determine you engine life. Once this blows, it will be 408 time. Th

 

Also I found the 4L80 to be a power pig. You should be over 500rwhp to really benefit from the 4l80.

 

I don't see any reason that the 5.3L can't handle the same numbers if it's tuned in right. Hell, Parish ran 18psi on his stock 4.8L.

 

Yes but the 4.8 don't have the same dished pistons as the 5.3. HE also ran 14 psi with a 75 shot with the 6.0......
My guess is that the top ring land is WAY thinner on the 5.3 engine than any other LSX piston...

 

It would be cool if a shop with all three diffrent pistons could throw a caliper on the them and confirm what we are thinking.

 

I was thinking failure would start right between where the dish's radius gets close ringland underneath if that makes any sense. Like where the material is the thinest. Maybe the 6.0 doesn't have such a thin spot. Another thing could be that since most people that have 6.0's have already killed a 4.8 or 5.3 and their a little more cautious and conservatives with thier tune.

 

Yep, I think that might have a little to do with it. lol