You might need to switch helmets. I had a white zamp helmet which made me look like this (imagine a korean guy wearing the helmet) since it was very dome like...
So I would drive with my head kind of tilted or I was reclined back a tad...then my head was still jammed against the headliner.
I switched to a Bell M2 and I have a lot more room. And the guys at the track aren't snickering and cracking Spaceballs jokes at me any more.
...just an idea.