For the coil, it has to do with mounting positions depending on coil type either oil, epoxy filled or e core type coil. Best to see manufacturers install recommdations. MSD has a coil that can be mounted in stock position. Usually epoxy filled and e core coils can be mounted in any position. Where oil filled usually needs to be mounted vertical.
For the 6al I like where 1wild R/T mounted his. It’s inside just above ebrake. Looks like he made a flat aluminum mounting plate.