How about a shorter ratio rear axle .
I may have one.
Depending how healthy your motor is.....
How about a shorter ratio rear axle .Not to steal the thread, but I wonder if there are outfits that can produce adapter plates and such to hook up a non-Benz tranny. That poor three speed really sings at highway speeds. I'd love to find something to bring the revs down - maybe a chevy 5 speed OD...