225, I think what I wrote to you in response to your private message is relevant to the overall discussion so I'll repeat it here and add a little extra detail...
I've done a ton of research into doing the Godzilla swap and, as I see it, you have two options since you already have the donor vehicle... (actually 3 but #3 is pretty advanced and more for the extreme performance crowd)
1) Completely gut the donor vehicle of every module and wiring harness and transfer all of it over to your current van (including the dash). The two vans don't share the same electrical architecture so nothing will integrate in a "plug n play" sense. You can see many differences within the factory wiring manuals.
This method is probably the simplest because you're dealing with two Eseries cabs where mechanically/physically everything is the same, it's just the wiring and computers that are different. The drawback is, (to my knowledge...as of my research a couple months ago) none of the tuning companies support the 2021+ Eseries platform so you're stuck with factory tuning and no easy way to manipulate any modules if needed. Vans and trucks use some of the same hardware but (from the info that's been given to me) the OS is different on the commercial vans and it's not a direct 1:1 match in tuning tables or PIDs. So nothing that's been done in the exciting world of Godzilla swaps in the aftermarket will work on the Eseries hardware.
2) The second way is to buy a Ford Performance controls pack that supports the 7.3L and integrate that into the van's wiring. This allows you tuning access via HP Tuners should you want to upgrade the cam and heads. This would be the path I take if I were to do the swap but instead of the 6R140 trans that comes in the vans, I'd use the 10R140 from the trucks. A controls pack for the 6R140 exists I believe but if I were starting from scratch, personally I'd use the 10-speed.
Either method you choose, it's not an "easy" swap. You're definitely going to want to find factory wiring manuals for both vans and become very familiar with them. And find a tuner that knows swaps pretty well or be prepared to learn a lot about tuning software...
For anyone pondering a Godzilla swap, the good news is that the engine was already fit in an Eseries so mechanically, placement is just a matter of buying the parts (motor mounts, radiator, etc...). The bulk of the effort to do this swap is in the electrical integration. In the 2008-earlier vans, I think this would be relatively easy since much of the van was still hard-wired rather than CANbus. For 2009+ vans, integration is still possible (I did it with the Cummins) but you'd have to think about things like aftermarket gauges and some lost functionality unless you reeeeeeaaaaaallllly dive deep into the electronics.
Currently you can buy a brand new 7.3L crate engine with a new 10R140 trans and the controls pack for ~$18-20k. I've got nothing against buying a salvaged rig, I've done it with great success but for those who would want brand new with known history, you can get a complete package directly from Ford now.
https://performanceparts.ford.com/part/M-9000-PM73A
For the last 2 years at least I've been trying to justify doing this swap for myself but since I don't have a van to do it in and I have two other engine swaps in the works (2.8L Duramax for one rig and a L83/6L80 for another), I'll have to wait for a willing customer to have my Godzilla fun.
To be clear about something above...I'm not saying it is impossible to tune Eseries vans...what I am saying is that the Eseries isn't a large enough market to devote tuning resources to, to the point where you could do the same amount of manipulation as you can on the truck version. There's no market for whipple charged delivery vans. If you want to use the Eseries pcm and do a swap, I'm sure someone could do it but you're going to be limited in what you can do for upgrades/tuning/reprogramming modules. The point is, there isn't going to be anyone (or very few someones) to help. You're on your own, forging new ground. If you use the truck PCM, there's a pretty substantial aftermarket going after this...not as substantial as the LS scene but there's enough going on in the Godzilla world that you'll find some good support no problem.
