I'm putting the OM617 into an 81 Courier, not the roomiest vehicle and I will have to cut out the firewall a bit to make room, but it'll be worth it.
The turbo 617 out of the box is comparable to the carbureted Ford 300-6 in power, power curve, and longevity. I have a 78 E150 with a 300 that will get an OM617 and MB auto if I get another one dropped in my lap.