I’d be interested as to why these companies say no. I’d suspect that parts availability is the concern.

I can’t imagine that rebuilding one of these is that much different from an antique tractor, wwII truck, etc. stuff that folks would have interest in rebuilding.

I’d probably look for someone that works on old tractors or old collector cars.

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)