Junkyard is the best way to go, I got my 99 vortec out of a suburban with 11k miles on it, look for one that has been rolled and has no front impact, the truck mine was pulled from rolled on the way home from vegas, totalled it but it was a slow roll a few times and didn't damage the engine at all. If possible have them run the engine for you at the jyard, they did this for me and as well tested the compression for me while I was there ( i think?), anyhow they definetly did run it for me. Forget the ranger torque splitter, I was VERY unhappy with mine, loud, expensive and shifts like there is a pound of rocks in the case, very annoying whining sound on the freeway as well. I am in the process of replacing it with an nv4500, either this or an auto would be my reccomendation. Also, if you can get a manual computer (impossible) for your vortec from a junkyard grab it as you won't need to reprogram it. Some say you don't need to reprogram but I ended up having BTB ($$ - ouch) reprogram my computer. It ran before having it reprogrammed but I wanted everything perfect and wanted to lose the fault code lights.
HTH,
noah