ZZP has brand new LDK (turbo) crate long blocks in limited quantities at the lowest price they’ve ever been. If you go that route and use a supercharged donor (rather than a turbocharged one), you will be in for a giant wiring adventure. The engine harness can be bought new for about $280 but youll also need to buy a matched BCM, PCM & TDM, a new PCM body harness connector, fuel pump and a full rewire of the body harness side of the PCM connector. Its not worth buying body or dash harnesses new, $$$$ for something you’ll just be stripping apart anyways.
The PCM connector and modules can all be had for under $400
For the crate longblock you’ll need injectors, a full intake system, all fuel lines & regulator, alternator, and several brackets.
I went this route and found a supercharged SS donor for $300, mainly for the transmission, subframe, wiring, and a few other compatible suspension parts. I am sourcing much of my other parts from pull your own yards or new.
In the end this route is no cheaper than snagging a decent running auction donor and certainly a LOT more labor intensive, but I wanted a brand new turbocharged engine.