I spent the day yesterday with my friend Bruce installing a slant six in his 47 Dodge panel truck. We came across a question we can't answer. We need a rear sump oil pan, but could only find a mid sump and front sump in my parts stash. The question is what vehicle used the front sump pan? We thought we were pretty smart about mopar and slant six, but can't think of what used that oil pan. Anybody need one? Trade for a rear sump? I don't have the oil pickup for the front sump and would need it for the rear sump if anyone is interested.

I have never seen a true factory front sump pan for the SL6, although the 67-72 pans come within a few inches of the front.
You may want to convert your current rear sump pan to a rear sump unit.
Check this idea, what if you cut-off the pan's front and rear gasket flanges and swap them "end for end", that would save you some cutting & welding work. Or use parts from 2 pans to make a new one.
DD