I recently replaced the engine in my 300SD with a much stronger one that supposedly had well over 240K on it. My old engine had 217K on it, burned a quart of oil every 1700 miles and had a lot of blowby. My "new" engine has hardly any blowby and in 3000 miles so far, it hasn't even burned 1/2 a quart. I'm guessing that the peppy car you drove just had really good compression, as well as some of the tweaks mentioned on other posts. Linkage setting is also really important. The turbo on my engine kicks in before the pedal is even 1/4 of the way to the floor. I've driven a few 617s that required the pedal to be almost 3/4 to the floor before the turbo really kicked in.

It's really nice when you can drive one of these old diesels without too much pedal travel. My right foot used to get really tired while driving a 240D.

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'81 300SD