I'm doing this exact thing. I purchased the Mancini bracket and it still has an offset. How did you work this out? Do you have pictures of the finished product?
Yes, the angle of the 2bbl rod is different than the 4bbl rod. Some folks reuse the 2bbl rod while some find a 4bbl rod.
Here's a thread that shows a comparison between a 2bbl rod and 4bbl rod. [WANTED] - 4-bbl kick-down rod