So, if you didn't know, and you probably didn't, I didn't... Mercedes uses liners on these engines. No over sized pistons are available, off brand replacements are over 100 bucks each.
I'm the king of finding things in junkyards, haven't seen one of these from GR to Pontiac in 8 months of looking twice weekly. Not even one I missed someone got before me. I'm guessing rust and poor maintenance claimed them awhile ago.
There is one longblock available near Flint for 200, pulled for low compression, so I may well end up in the same boat. There is a set of pistons and rods on ebay, but they come in 3 sizes, 0, 1, or 2. And you may get all of one, or a mix of any in an engine. Mine was all 1's and 2's, new pistons could be all 0 for all I know. Then they'd be .002 undersize before I honed it.
I'm a real, do as little as possible kind of guy, slam it together, have fun. This kind of shit gives me anxiety, because it's precisely how projects wind up half finished, for sale, trying to desperately get 50 cents on the dollar because "life happened".
But, the wife is on board, she very much wants a small diesel 4x4, so.. I gave pulling the liners myself a whirl. Paying a shop 500 bucks to pull and 500 to install wasn't in the cards at all.
Ran some hot beads up and down, sat there had a beer or 3 until they stopped snap, crackle, and popping... I welded a little (large) turd in the bottom of each for a chisel to hit... Once they were cold, they tapped out fairly easily... Took about 2 hours with waiting and misc struggling of running out of wire, etc.