I've done a couple motor swaps, and you will spend more than the $8,500. I've swapped two 3208's for 8.3 cummins in a couple crane's, and its really time consuming. It's not impossible, just a lot of fab work and that takes a lot of time. A full donor truck would make a big difference, but it sounds like all you have is a engine.
Just for example of things that took time. New front and rear motor mounts, new throttle linkage, New power steering location (lines), change air compressor location (line change). Alternator and starter changed location, so new wiring from batteries and to cab. New radiator hoses, may have to have radiator reworked with additional water ports. Intake piping, exhaust routing. I would change clutch while you are there.
Every time you change location of something (air comp, power steering, starter), you end up spending 1/2 a day moving everything to fit, and getting lines. In the cranes, just the throttle linkage is a all day affair. And it all added up.
The first engine swap took about 5 weeks from the time the engine went down, until I was back running again (part time/ spare time work on it). The second swap was just like the first, and we had all the parts we needed when we started and it was a week start to finish. Not 5-8hour days, but close.
The truck swap will be easier than the crane I did, just because the access is better, but I'd figure on it taking week or two.