LS Engine Swap question... What years??

[Tetanus Express]

Ok so I've done a bunch of reading and figuring on what LS Swap to go with. The truck is a 85 C10. The main question I have is what year or years is preferred when looking for a transplant donor engine? I was thinking of going with the 5.3 and 4L60E or 6.0 with 6L80E combo. If you were going to do a swap what year would you prefer? What would you do differently? Are the earlier years easier to swap into a standalone type configuration or later years?

Thanks