Great information Dave! Out of interest, would your suggested 6.1 swap using the existing 5.7 tuning include using the 6.1 intake manifold and exhaust manifolds, or would/could all of the existing 5.7 induction and exhaust components be swapped over, including injectors, etc?

Kind of hijacking the thread a bit, but I am starting to plan the outcome of my 2016, as it will have over 200k in the next 3-4 years. Could a truck 6.4, or car 6.4 (bottom end and cylinder heads) be swapped into one of those with the stock 5.7 tune, using all of the 5.7 induction and exhaust components in order to pass CA visual examination? Of course, I would be beefing up the 65RFE trans as well.

My son had a bad experience with leaving the MDS lifters in his 6.1 that we swapped in to his 08 2500, after 7500 miles exhaust lifters on #2 and #5 (if I remember correctly) collapsed . which lead us to swap in a 6.4 BGE. the 6.1 had 13k on it when he bought it.

On the tune....when we did the 6.1 swap it ran good, definitely could feel the difference. after he got it tuned it was much better, tore up the 545RFE in about a month, then we swapped over to a 46RH tossed f--k ton of codes, had to buy a Manual 2500 Truck ECU/PCM then sent that to out to B&G for VIN flash.

Search around for a 6.1 some people want gold for theirs , we just pick up a pair off of CL out of Central NJ for $2200, 06 Long block 110k miles, and a 2010 short block with 65k

your 07 Is it 4x2 or 4x4 ? my kids 08 is a 4x2. 2500 Regular cab long bed.
Swap the whole 6.1 over, the 5.7 intake will bolt on but the ports are different enough that it's becomes a hindrance in performance.
I can tell you from personal experience that the SRT8 exhaust manifolds will not work in a 4x2 , the passenger side hits the frame rail. we used a set of JBA headers and changed the flange, I've seen my buddy do a few 6.1 swaps in to 03-05 1500s and the 5.7 headers work fine for a stockish build.

As for your 2016, Yes the 6.4 short block with either the stock top end or the (eagle)top end with the 5.7 intake can be swapped in and use the stock tune...but keep in mind that a tune will make it issue free.

My experience,
The 09 1500 I bought back in june we swapped 2016 6.4 in it, ,used the Eagle intake off of the old 5.7, had some start up issues with it ,keep running lean after about 4 hour it sorted it's self out, ran fine for a day or two , then the next day it would throw a fit , after an hour of start ,die ,start run 5 mins,die,start,die,start run 5mins, die, it sorted it's self out ran for fine for a day, then back to start,die crap, . this went on for 2 weeks then I got a friend of mine to "tune it" I bought HPtuners for the truck ,all he did was go in to general under engine , and change engine size and displacement from 5.7 to 6.4 , left everything else stock, and it's running great since ever since fun truck to beat on.

Now my buddy Ric, when he swapped the SRT392 in his 2014, he also changed the heads and intake over the the 5.7, dropped it in and not one issue, he says the difference was the ECU/PCM then went in to a half hour of an explanation that was WAY over my head....it was one of those just node and say , Ok I understand type conversations.
.

Wow..I'm grateful for the input here!
My truck is a 2wd, regular cab with the 545 trans. 340,000 miles on everything. It has been well serviced though. I do have a cold air kit from K & N. The exhaust is stock to the bed, from there it is a single inlet, dual outlet Flowmaster.
The 6.1 engines I have seen listed here are over $4000. They do come with warranties but I don't know how soon I could do this swap. I've ran into situations where the warranty of something runs out long before the part is ever put into service.
A long stroke rotating assembly is $2300. This takes a 5.7 up close to 400 cubes. That was one of the ideas that I was kicking around.
This truck is used for work...I'm a Carpenter and do a fair amount of commuting. I also use it as my primary driver. I am interested in a modest power increase but not one so much that I start spitting transmission parts. What kind of real world increase can be expected with those JBA headers and a 6.1 cam? I'm keeping the MDS.
I am not against using a 6.1 if I can find one reasonably priced. I'm not going to spend $3500 on a used engine. If that is the going rate, I'll stick with a 5.7.

30 hp from the cam and Headers might be more depending on the condition of what you have now.

Thanks. I figure after all the miles I've racked up, an engine with 240,000 fewer miles SHOULD make more power!