At a wag I"d say you"re looking at 10-20 to do the carriadge over, depending on what it needs. If you have to change bottom rollers and track pads you can plan on the upper end. I doubt you"d get more than 20K for a 6C with a new carriadge so I"d plan my offer around that... The rest of it is just an old dozer. 5-10K top should buy it.