I found a rebuilt head for $945 including shipping. It is from a 1991 300SDL 3.5 liter. Seems like a decent deal, but before I purchase, can anyone tell me exactly what modifications are needed, I understand the prechambers need to be milled a bit, but not sure about other mods. and their respective difficulty for a mechanic who has never worked on a 300SDL diesel before? Am I going to have to purchase a prechamber removal tool and other tools?

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Mercedes Fleet:
2004 CL600 Designo Espresso SPORT
2004 S600 Designo Espresso SPORT/Lorinser Pkg.
1999 S320
1988 300TE
1972 280SEL 4.5
Diesel Fleet:
2014 GL350 Blutec
1987 300SDL Blk/Blk 4 place seating #18 head
1987 300SDL Smk Slv/Burgangy #17 head
1986 300SDL Blk Pearl/Palomino #14 head w/ 280K
1984 Lincoln Mark VII Fact BMW Turbo Diesel