The only thing I follow is to use late rocker arms with late cams, early with early and don't mix them. Also the threads holding the sprocket changed (you don't want to drill and tap the cam on the car when the only sprocket you have won't work).

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Hanno
'79 6.9 Sold (after 27 years)
'83 280SL, 5 spd.
'94 E320 Sdn. 5 spd conversion
'02 E320 Sdn.(on loan to mom!)
'87 300E (5 spd. conversion) Sold
'05 E500 Wagon