Fisherman, we may be in the same boat and without oars , not good.. I have yet to order anything, this Benz is not in the best of condition.. Body rust, the two front fenders and the RS rocker panel.. Now I fear it is burning oil.
You may be able to restore your engine compartment vacuum controlled ACC temperature control unit, used from '77 to 80 or '81..
Hopefully it is in better shape than mine - cracked, corroded, clogged, and corrupted.
$289 is by far the best price, I recall $225 just for the rebuild kit..