Does anyone do a conversion for a W124 wagon to either the 4.0 or 5.0 liter V8 engine?

Is it hard to swap out?

Neil

Since the W124 chassis was never intended to carry a V8 there were many modifications done by the factory to the chassis itself. Retrofitting those changes would make any project either A: cost more than its worth, B: a legendary pain in the butt, or C: doable but you will always have problems. Second, there was never a 4.0 M119 motor. The DOHC (M119) was, is, and has always been a 4.2 liter V8 or a 5.0 liter V8. Megabuck tuners can do the job but expect to pay mid to high 5 figures. If you notice when broswing the tuner webpages that they only list mods to given models.(they will put a 6.0 V8 in a 4 or 500E but not a 300E.) The amount of re-engineering to make a 500E wagon or 500CE isn't worth the effort in my opinion. But if you really have it for a V8 wagon you can call the tuners, try to import a V8 wagon, or turbocharge a 6 cyl model.
That is my two cents....but its definitly your call.
Lee