Yeah, they're rare, but I know a few guys here have converted them, and others have euro cars.
What kind of mileage do you get with a stickshift 300? Especially in the older (lighter) bodies?

I really love my '71 220D 4-sp, and I'd love to drive it more often, but the RPM-limited cruising speed, power-limited top speed, and lack of power for climbing hills and passing is just a bit more than I think I can do long term. Of course on the flip-side, I'm averaging almost 30mpg in pretty hilly terrain and wouldn't want to lose that either...

What kind of mileage could I expect from a W115 with a 300D and a rear gear better for the highway than my current 3.92?
What troubles would I run into trying to put a 300D and the appropriate rear gear in? I'm just kinda kicking this idea around right now, but it would be cool to know if it is reasonably do-able (without huge cutting and welding on my car) and would give the results I want.

__________________
1971 220D/4-speed ~250K mi. Family owned (dads side) through three generations since <5K miles.
1992 Chrysler LeBaron, 3.0V6 125K. Family owned (moms side) through three generations since new.
1977 Chevy Camaro Continual hotrod project
1970 Cadillac Sedan DeVille 472ci and nearly 19' long
1974 Fiat Spider Still needs work

Not exactly the exact answer to your queston but, since I have two manual trannies I'll chime in anyway...

1983 300TD (w/turbocharged 5cyl, 4-sp manual) 23mpg in town, 26-27 mpg hwy.
1975 240D (4-sp manual) 28mpg

__________________
Never a dull moment at Berry Hill Farm.

so I don't know about the milage, but having a 300d stick is awesom, I have oversize tires on it in lieu of a more hiway friendly rear end. Its an interstate cruzer, turns about 3700 rpm @ approx 85. (speedo doesn't work so hot either)

__________________
Cheers,
Robert

well, from some searches, it seems like low 20's in the city and high 20's highway is about the norm for a 300D, but I am assuming 90% are automatics and in heavier chassis than my W115 (3200# with me in it)
LOL, it's only an 80hp engine, but that's be a 33% increase I see what you mean about it being a blast to drive!

Shoot, is it possible to have a 300D and keep the gorilla knob? I really like it!

__________________
1971 220D/4-speed ~250K mi. Family owned (dads side) through three generations since <5K miles.
1992 Chrysler LeBaron, 3.0V6 125K. Family owned (moms side) through three generations since new.
1977 Chevy Camaro Continual hotrod project
1970 Cadillac Sedan DeVille 472ci and nearly 19' long
1974 Fiat Spider Still needs work