I wish I were closer . . . (I'm in VA)

I converted a d24-powered 245 to b230f some years back. While most of the diesel-related parts--and the car itself--are long-gone, IIRC the actual fuel tanks (gas and diesel) were identical--it was the pumps and fuel level senders that were different. The diesel wiring was also pretty straight forward--you could probably build a harness if you were unable to find one in suitable condition (the insulation on the one in our 83 was completed rotted away).

You may want to check out the "green books" (tech pubs) at the following:

http://www.k-jet.org/documents/greenbooks/200-series/

For example, the 1981 wiring diagrams include some of the diesel information you'll need to do the conversion:

http://www.k-jet.org/files/greenbooks/TP30316-1_wiring_digrams_1981_all_models_part_1.pdf

and

http://www.k-jet.org/files/greenbooks/TP30316-1_wiring_digrams_1981_all_models_part_2.pdf

Also, D24 engine maintenance-related:

http://www.k-jet.org/files/greenbooks/TP30420-1_d20_d24_repairs_part_1.pdf

and

http://www.k-jet.org/files/greenbooks/TP30420-1_d20_d24_repairs_part_2.pdf

D24 engine reconditioning-related:

http://www.k-jet.org/files/greenbooks/TP30224-2_d20_d24_reconditioning.pdf

IIRC, the diesel 240s had unique front springs to accomodate the heavier engine. They also had the vented front brakes for the same reason. Ours had the BW (55?) 3-speed auto transmission. I'd look for a manual box instead.

Good luck with your diesel!

Steve A-