I have a clearance issue with the drag link at the pitman arm. It currently has a 3” drop pitman arm, 3” shackle lift with a 1.5” OME leaf spring. The drag link at the pitman arm clears the oil pan by a half inch to 3/4”. I swapped a Mercedes 240D engine into it. What can I do to give a little more clearance. Thanks.

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Not much without relocating the steering box.  Most of the time we are trying to get the drag link higher and more out of the way, so there isn't much for making it lower then using the drop pitman arm, which you are already doing.

You might look into modifying your oil pan to give you the extra clearance.