Looks like a good start! You have made some good decisions by dumping the whacked up frame and that bumper
My buddy has a 6.2 in his K10 with a 4 speed and he gets 21 mpg! So needless to say I hope you can expect the same results. I don't know much about the swap but I'll tell you what he told me. He said if you can get a harness off of one that came in a box van, basically a chassis van, it will make things a ton easier. I guess the way they did those harnesses it's all self contained to the engine. Like I said I don't know much about the swap but I hope that kinda helps! I'll be watching your 52" conversion too!