I have a non-turbo 617 engine (300D) , and a Turbo 617 (300SD).

The water pump pulley on both appears the same diameter. Have done water pumps on both and have had pulleys off.

At the junkyard today went to get replacement pulleys for the 300D.
I wanted double belt water pump.

The first car I took pulleys from was 82 300D turbo. The water pump pulley hit the lower pulley coming off and is larger, by maybe one half to one whole inch.
This particular pulley actually had an MB parts stucker on it. Could not read the part number. But the pulley seemed new.

On a second car, a 84 300SD 617 turbo I noticed the pulley on water pump was smaller, like I was used to.

Smaller pulley, faster the water pump spins, larger pulley , pump spins slower.

My question to you all is:

Did they offer two pulley sizes on Diesel MB's in the 1980's and does
anyone have any background on this ?

I went with the smaller one that matches my current pulley diameter.

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250