Be careful most coils are not designed to run upside down. If they can they are usually the potted type and not oil filled. Running oil filled usually results in a longer term fault but I could certainly see how the secondary could short out if not fully immersed in its oil bath. That's there for electrical insulation and thermal management.

I put my coil and ignition box inside the car. Glued wood up high inside the firewall to mount things. Only the large wire comes through the firewall.

Kitz