I don't know what the horizontal oil-filled deal is - yup, factory did it, and mine I referred to sat there from 1988-2014. I've owned a bunch of stock '67-up Mopars with their original coils, up until around 2000 when I most of them off. But I've heard before that oil-filled coils are not actually full, and get hot, which I guess creates resistance in MSD boxes? Nevertheless, that F150 epoxy coil works great if you don't need stock-appearing.