I have recently driven multiple in my search for a low mileage 300D. I personally wouldn't describe what I experienced as Slow...Certainly not Fast by Any measure, but not slow...0-60 times are just over 12 seconds with your foot in it. I personally don't consider that Slow for 3600 pounds and close to 40mpg.
One reason the car feels slow is one of the most common rear gear ratio's for a 300D is around 2.8 to 1 (2.65 to 3.07 depending on year and model) with a top speed around 110mph...torque multiplication helps acceleration significantly and the 300D's were certainly set up for economical daily driving, not to be a 'fast' car. It takes a LOT of torque to make Any vehicle with gearing around the 3.0's to feel Fast (as its not being Multiplied by as much a factor before it is delivered to the wheels...)
If you are running 33's or 35's and say, 4.11 gears, the 4 speed auto behind an OM617 will still deliver highway speeds and close to or over 30mpg in a Waggy (a 5 speed manual would be better still). Personally, I'm not looking to drag race a lifted, larger tire'd vehicle or cruise at 95mph. I'll take out the S-10 if I want to haul booty (at Speedworld Raceway in Surprise, Az. usually...was a BBC, now a 406SBC)
Another point, it is easy to have the pump squirt more go juice and have the turbo stuff it all in a little harder and significantly increase power output without sacrificing reliability under normal operating conditions. The AMG version cranked out some SERIOUS power (over 400hp)
Sorry to rant, but even looking at the OM617 swaps on Youtube clearly show that you can move a 4000+lb vehicle pretty well...
The fact is, with out purchasing anything aftermarket, it would be simple to make more torque than Any V6 or I6 that was ever installed in Any Wagoneer from the factory...(more boost, more fuel) If you consider the AMC 4.2 (approx 240ft lbs) engine a slow, inferior power plant then we are in agreement, it would be Slow.
A larger turbo + injection pump work (swap the elements for the larger versions offered and again, turn up the full load fuel delivery) and make similar or more torque compared to any stock V8 that came in any Wagoneer (over 400ftlbs) at the cost of efficiency... which is Not what I am looking to do, personally, but could be done none the less.
I certainly respect your opinions on the matter, I just happen to disagree. Check out youtube, some pretty nice OM617 swaps and even some 0-60 runs.
I hope this post is not taken the wrong way, I am not trying to ruffle feathers, but I am Confident in my decision to swap in a Turbocharged OM617. It will easily generate around 250ft lbs (or more on demand for short time use by using a boost controller as opposed to its current setup for limiting boost pressures) and adjusting the amount of fuel it delivers when boosted to those levels. They make 180ftlbs at 2400rpm Stock, limited to approx 8psi from the factory (most people seem to measure them waste gating around 7psi factory)
One more detail i checked on was that it weighs virtually the Same as a Built 401 (technically a few pounds less with a Claimed weight of 565 and the 401 tipping the scales with a claimed 601)
If you cruise Diesel forums, you will find Many Scouts, Cherokees, Comanche Trucks, Full size blazers, full size trucks, too many to list, that have OM617's that are 'turned up' and make well over 200ftlbs with only 12psi...the stock turbos will go up to around 18 or so I've read, though I never like to push equipment to its Actual limits.
Do consider that 4bt's only make 215ftlbs stock....and that is a Very popular FSJ swap...(and thats the highest Stock torque number I saw, many versions of the 4bt make less than 200ftlbs from the factory)
I can have an acceptable mileage Full running 300TD complete car for 2k or less and have every last little part (other than bits of steel for remaking brackets/crossmembers/motormounts/etc) to do the swap.
Again, sorry to rant...I feel I've done my homework and there are still many other reasons I find this engine handy (Max engine rpm is Significantly higher than the 4bt for getting the tires spinning in the mud, for another). I see this engine as a Lighter Weight Equally Powered Equally Reliable Much Cheaper 4bt.
P.S. Absolutely NO disrespect meant to the posters (and non posters) who disagree with me and to be clear, I LOVE the 4bt and 6bt engines for many reasons, I'm just in love with the overall package the OM617 delivers for a fraction of the 4bt cost (at market value, special awesome deals excluded from that statement