Didn't want to let this die off and I had forgotten to update this. I found a high mileage 5.3 with a lifter tick (but ran strong and had decent power) for $150 - complete, including harness, PCM, fuse block, etc. So I picked that up unexpectedly to teach myself to rebuild. Its under cover right now but I'll be disassembling it as I can and bringing pieces actually into the house to rebuild them, keeping it protected and fogged with oil as parts come inside. This is purely a learning experience, so if I find something catastrophic, its not a big deal to me. It will ultimately, as long as the block is in decent shape which I suspect it is, get rebuilt stock-ish, then turbo, then forged internals with a 4" crank and .030 over to keep pretty thick walls for more boost and put into a semi-dedicated "budget" race car (i.e. fox body mustang, 2nd or 3rd gen F Body, etc.) Thats bucket listing though so for right now, its just a base for me to learn internal engine work for now.
I also have basically taken possession of my donor vehicle. I don't physically have it - I have to sell a couple of vehicles first to make room for it here but I should have it here no later than April (approx 2 months ahead of schedule.)
Confirmed its a Z code flex fuel (L59) with non-CasTech 706 heads. Other than frame rot its actually extremely clean so I am hoping to fund part of my swap by parting out the remainder of the Yukon. All I'm using is parts of the exhaust, the engine/wiring/etc, gas pedal... everything else will be posted locally. Engine has under 50,000 miles on it so I plan on keeping this pretty close to stock. There's some history with this engine that I'd like to not take a chance of completely blowing it up until I can rebuild it myself. Hah! I know its quite a bit of work to swap engines back and forth as I rebuild the cheap high mileage core I picked up but I really don't mind - its good practice and I enjoy it. I also have the stock 79ish SBC and TH350 I have to figure out what I am going to do with. Do I teach myself to rebuild transmissions on the TH350? Do I sell it as a rebuildable core? Same with the 79 SBC. I'll probably just sell that as a running engine that could use a refresh since I seem to have settled on or at least focused on Gen3/4 SBC's vs. Gen 1/2's.
Its been a wet winter here - snow followed by rain and then sub-arctic temperatures so everything is ice, which means no progress on my truck at all. I'm OK with that. I've pushed body work (Besides floor board and a new spray of sealer/primer) to this summer and am focusing on preparing for the drivetrain swap by collecting parts and tools needed.
Hopefully everyone is having a good and productive winter!