Well I am going to be the opposite of them. A good friend of mine traded her Eldorado on one of the first Cad Escellades with a 6.0 that went on sale here locally and while that thing would romp when she wanted to romp on it it was dead nuts reliable and she never had any trouble with it doing big harry burnouts on it's own. There is so such thing as too much power, but there is such a thing as too little brain power for the horsepower you have on tap.
The thing for me is = is it cost effective for you to buy the complete van, pull the engine and trans and what ever else you need to have it run in your truck without issues while selling off the usable left over pieces starting with the ones you just don't need like lights and seats and going from there. The salvage on that new of rig with that engine and trans has to be pretty high unless you can get a real buddy deal. On Ebay the asking for a 2015 6.0 with 4LE60 is 5500 us
https://www.ebay.com/itm/2015-CHEVY-...8AAOSwnd9d~Sm- and I'd think that 2019 unit with the bigger trans is going to bring a fair amount above that..