Found an on line catalog from AP Exhaust. Looks like they show a system for 88-91 760/780. No notes on if it does or doesn’t fit independent rear suspension. The bend over axle is two pipes separate from mufflers. Maybe twisting and angling of the two pipes will allow universal installation on both axle versions. All 4 cylinder parts are different than 6 cylinder parts per catalog.
Check it out http://www.apexhaust.com online catalog, page 611, image 10712
Have messaged a re-seller to see if they can still get stock, will let you know how it works out.
Dan, Will check out Rock Auto, thanks for the reply