hey guys i found a l20b motor attached to a 5speed out of a 77 620 and im gonna pick it up and drop it in. my 72 510 goon is all stock with a l16 thats bad and a 4speed. i know i need to get the driveline shortened and balanced, and i was wondering what other mods will be done. i know the oil pan and sump needs to be switched from the l16 also, do i need to get a custom x-member for the tranny? thanks in advance!