It's actually the 300SD that I posted about in my "turbo seals" thread a week ago...don't know what I titled that thread now. there was good advice in there that I can't act on until I go home for another weekend.
I burned through 5-6 quarts of oil (blue smoke lingering around curves going up the mountain) in less than 250 miles on the first big trip I took in the SD and it's got too few miles for bottom end wear (rings) to even be a serious factor. My thought was turbo seals, but my dad did Brian's "3000 RPM with no load should produce the same smoke as you were seeing on the road" test, and it didn't smoke that much. We're still checking stuff. The air filter area is very oily, and so our next place of diagnosis is to see if the separator is working okay. If the separator's check valve were plugged up or something else is wrong with it, then perhaps the oil is burning because it can't drain back. But anyway -- let's not derail the OP's thread any further. We can move this to my thread here
http://www.peachparts.com/shopforum/showthread.php?t=288033