Decisions, Decisions.....

[mopar250]

Hey guys,
Am starting my LS swap in my 80 swb and have a couple local choices for engines that id like some opinions on.
First a yard in town here has a unknown year and mileage 5.3 for 350. Nothing included.

Another yard has an 04 5.3 with 90k, tested, nothing inculded for 600.

The third yard has a 6.0, over 100k, tested nothing included and wants 1050.

I am going to swap any of them to an ls1intake, rails ect, and will have a new harness made. The 04 I assume is DBW but i will just get an ls1throttle body and switch it (as long as i'm correct that I could do that). The truck is just my fun truck and eventually i'll put a cam in the motor and have fun but will run stock for the first year or so to make sure ive done it correctly. So, which would you choose and why?
Thanks!