I decided early on to go with LS engine power. You hear about people getting cheap or nearly free LS engines all the time, but I have yet to find one that doesn’t have over 300,000 miles or a window in the block. And forget about cheap 6.0Ls. It took a while and several lost bids on donor vehicles, but I finally scored at auction an incredibly crashed 2008 Trailblazer 4x4 with an all-aluminum 5.3 and a 4L60E (this is the good side). The truck had around 130,000 miles on it, and I was able to drive it to make sure everything functioned. It was around $1,100 by the time I got it out of the yard, but after lots of sweat equity and selling off good bits of the carcass, I ended up with an engine, transmission, and harness for under $500.