That truck pictured was built by a fellow Kentuckian. He built it for pulling in DHRA WS. By the time he got it together, it took a good bit mroe than a tuning only truck to be competitive even in that class and he just wasn't wanting to spend anymore money on it so he unloaded it. Last I knew, a guy in TN had it.
Anyways, it has the duramax gauge cluster stuck in the 80s model dash where the old gauge cluster was. The cluster wasn't done real pretty but functioned properly. They mated the duramax to GM NV4500 and np205 transfer case and retained the GM D60 up front and good ol' 14BFF out back. It is/was AWESOME! Painted it the Arrival Blue that GM used from 03-04 and looks spectacular. IIRC, it also had the steering wheel/column in it from the donor truck. It was right around the time EFI Live was coming out so it wasn't as well known at the time. They used custom tuning from TTS to get it running.
There is a thread in here where a guy is working on doing this exact swap to his 80s model truck with LLY duramax. I'll get the link in a moment.
I'm also doing one in my 83 GMC CC SB. I go back and forth on exactly how I'm gonna do mine. I have acquired a 2wd 06 D/A donor truck to rob the powertrain from BUT am considering using my complete 02 chassis and basically do a body swap.
The newer frames are a fair bit stronger and are already configured for the DMAX.
Thing is, the frame in the 83 is in spectacular shape and was cut down to a shortbed crew cab and I hate to get rid of it. Decisions decisions.
As for your questions... Yes, the Duramax can be wired up such that it doesn't have to have the duramax gauge cluster in it but rather aftermarket AutoMeter-type electric gauges. PPE can modify the wiring harness to be pretty much a plug and play affair for you.
There's several options on the drivetrain. You can (A) do like you said and run the D/A/NP261HD transfer case from a 01+ truck and swap a Ford front D60 in, (B) run a divorced transfer case (NP205 from an old Dodge or International) behind a 2wd allison that drops on the correct side for the GM front (C) Atlas makes a transfercase that will bolt right up to a 4wd Allison. (D) SunCoast makes a billet tailhousing for the allison that can be setup to run pretty much any transfer case - I'd go for a mated GM NP205 in this case so you don't have to worry about making a Ford D60 work, (E) I'm being told Advanced Adapters is also about to release an adapter to allow you to mate an NP205 to a 4wd allison (F) run a NV4500 5-spd with an NP205 mated to it and keep the GM front.
I had planned to do the divorced transfer case behind the 2wd allison since I got a 2wd donor but mine will primarily be a sled pulling truck and I'm being told that the NP205, while renowned for its strength in off-roading vehicles, is not gonna handle the stress and torque it'll see in a diesel pulling truck without substantial money spent. Kyle Michaels runs one in his Super Street truck but it has very expensive SCS billet parts inside it to make it last and is no longer selectable - it's fulltime 4wd LO. So that's kinda why I'm considering some other options - like the body swap - for the stouter transfer case and frame. If it's just gonna be a street/show truck and not see any motorsports competition then I wouldn't hesitate to put a NP205 or even better, an Atlas transfer case behind it. Ideally I think it'd be best to get a complete 4wd donor truck and convert the front to a Ford D60. REGARDLESS, don't just buy and engine and transmission. There are too many little things you'll wish you had from a donor truck once you dive into it. You DEFINATELY want to get a complete donor truck with everything still intact IMO.
There is a guy selling a "conversion manual CD" on eBay. His seller name is "pussow". I've purchased it, more for the engine mount designs than anything, but have yet to take a look at it. For the price of it, even if you get just one piece of useful information from it, it's worth it. He put it together while putting an 06 LLY (basically a detuned LBZ) and 4L80E from a van in his 90/91 V3500 show truck. His truck is sharp and the install looks good IMO. Like I said, to me, the engine mount diagrams are worth the purcahse price if I stick with the old frame.
Good luck!!