Fwiw, I believe only the 81-82's had the single row timing chain. The 83-85's had the double row. I don't know exactly when the change occurred, but it was somewhere in the 82-83 model run.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".