rebuild vs swap decisions

[Ironsled]

All right friends lets get some thoughts on this subject if yall dont mind
I have a cm2350 2014 550/1850
demandated with 588k on it
i have had nothing but problems all year starting with full dfp scr failure system $4800.00 so i was force to make a bad call getting me a bad delete tattoo $2600.00and being followed in two months later by a horrible 11 days on the side of I90 with fuel system failure $4200.00 where my knuckle busting time and a little help from Mr Hagg helped out
i was followed by pilot bearing, throw out bearing ujoints and carrier bearing, slip yoke and balance of the drive line had to all be done
i had clutch kit everything above done for $6000.00
but there is also something like else wrong i need to find while do this swap
this is all leading me up to here and now issues
i went down about 5 weeks ago and made it home and replaced my charge air cooler $700.00 and put new gaskets in turbo manifold $300.00 and my last few dollars had went into rebuilding my turbo he400vg that isnt available to the public from cummins so i had to rebuild it my self and it turned out great for $1048.00 . fired it up and after sitting 4 weeks in the heat, man was the motor dry sounding for a few mins .after a little while i shut it down and started cleaning up my mess . i went back with insite to get codes cleared up and watch some things . everything was looking good till i started hearing a loud tapping uper end towards cylinder 2 . killed it thought i better recheck my over head .exhaust was a little tight and jakes were pretty lose , intake was also just a tad lose.back together we went to find the same sound just about half as loud on my test drive #1 to town and back #2 of the 35 miles round trip.
i think i had a jake stuck from maybe a cloged oil way to it because i ran some of the insite test and all was good and passed other than leak down test that didnt pass in my eyes .cylinder cut out passed on each one running the same all the way across the board down to a single cylinder and everything was great "WAS" back to the test drive #1
after about 17 miles test drive #1 i stopped and surprisingly the sound was gone and damn she sounded better than ever before so im was all excited to get back out there working .#2 back to the camper i went.
next morning went to get my flatbed and went i started ole blue, up and wow was i surprised in bad way .
little bit of back pressure coming out of the breathers puff puff puff like it was missing or not detonating properly, i thought maybe maybe I pushed a liner lose when i first started it was a thought with that being said i dont think my tune is fully proper yet and with the exhaust back pressure now around 130 at idle 700rpm to intake pressure at 1.5-1.8 from a day prior the were with in the 2:1 ratios but now dies on cut out test on 2 cyilders and i got coolant leaking from the egr cooler clamp on the back end out it ....(note:there is the proper block plate between the manifold and egr cooler and after the egr valve just before the crossover pipe to the intake )
i did block test and its showing combustion gasses in the coolant .GREAT i thought well that is it im out im broke and no way to make it up. called the bank and said well where you want this pyle of problems left i have done all i can and all be damn they ended up getting it together and told me they would be better off with giving me the approval to get the money to fix it and keep me in the game . not knowing where to go from here and risking more money stress and more BS for the enjoyment of moving freight for what seems to be charity money for parts and fun times of living broke and broke down .
so here i sit and think i can do this how ever i got one more shot to save this business.

I have come to hate this motor ! and done screwing with it and to get caught up its going to have be a solid swap or rebuild where i can make a come back .
so my thoughts are lets take this cm2350 out and let the dog piss on it
and go back with a cm871 , have a bearing kit put in the tranny and do wheel-bearing and possibly change out the 3.36 ass end to a 3.55's.and get this blue angel the exorcism and rid her of her demons where we can make a run at saving our ass before i say screw it and take the camper and move to the cool mountains and whittle sticks and sell tooth picks and give up .
gonna be pulling a Conestoga going back out to work
so question who and were do i get a good cm871 that i can count on and have some warranty
any experiences with these guys ill list below??

{name removed}

and i know i want a demandated motor im done with that crap to
so gearhead mr hagg is best option yes but i dont know that i can get to them and if i can
if i can afford it shipped and get it done in time to save it
or these gliders engine kits are an option with warranty .
I appericate any one that takes the time to read this long ordeal and i apologize in advance for the story but best i tell it before the questions start flying .
ready set go
thanks guys