I did almost the same on my 340 stocker like Dave J showed, Long story short I used the small rear sump Magnum pan, used a 3.0 liter v6 oil pickup with modifications (3/4” inside pipe with the big bell) straight down into the sump, plugged the existing stock hole. Now I can use the one piece rubber pan gasket too. Also not using oil filter, lines running to the accusump, filter is a big oil restriction like a muffler