Gas to Diesel conversion

I have a very nice '73 450 SEL that I love to drive, but at 10-12 MPG, is expensive to operate. It would seem that swapping in a turbo diesel engine from a wrecked 300 SD would be relatively simple, but of course as they say, the devil is in the details. I have done numerous swaps/conversions on American cars over the years, but nothing this major on a Benz.

I could also really use the back seat room of the "L" 116 body, I love my 240D but it is just too small. I have had no luck finding a nice 300 SD that was up to my standards.

Thanks all,

Sigmet

'73 450 SEL
'80 450 SEL
'82 240D
'78 Ranchero