2017 Suburban 5.3 to LS3

I have a new Suburban with HD towing package (3.42:1 axle ratio) that I bought to tow my car hauler. I didn’t want a pickup bed. I used it the first time and am dissatisfied with its ability to hold hiway speed on cruise control without downshifting to a gear that puts rpms in the 4500 range. I was thinking about modding it with everything up to a turbocharger but due to the money involved not sure that’s the best course of action. Then I got thinking about changing the engine to an LS3. The mechanical aspects of doing a swap are not daunting. The computer controls are what I would worry about...connectivity. Does anyone have any idea of the feasibility of this project.

It only has 2120 miles on it so should be able to recoup good money on the 5.3.

Thanks in advance.

Put taller gears in it. 342's should not be on a "tow package" vehicle. 3:73 or 4:10 would make it tow good

Yes, that is under consideration too. However I’m not sure about the cruising rpm and it’s effect on fuel economy. I’m really trying to see if anyone KNOWS what it would take to upgrade the engine to an LS3. Thank you.

Little quick math with gear ratio and tire diameter and speed will tell you exactly cruising rpm. Probably even a calculator online that you can punch the numbers into