I would find another and use your good parts to bring it up to your standards. You can usually find one on ebay or this forum 1984 W123 Mercedes 300D Turbo Diesel but any local import garage might have a line on one with a dead engine.
Good Luck.

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Ncnetman
1978 300cd fresh paint
1965 Mustang
1968 Torino GT fastback
2015 VW Passat TDI
1969 Ranchero- project
1974 240d 4-speed -for sale
1976 240d - for sale
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1959 Chev 3100 Fleetside - sold